Spinal Fusion Cage with Removable Planar Elements

ABSTRACT

The present disclosure relates to an intervertebral fusion cage that is equipped with generally planar elements disposed on at least one of the top, bottom or lateral wall of a fusion cage, such planar elements reversibly covering at least one opening to prevent leakage of fusion promoting material.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/473,366, filed May 16, 2012 (now U.S. Pat. No. 8,292,960), which is acontinuation of U.S. patent application Ser. No. 13/277,272, filed Oct.20, 2011 (now U.S. Pat. No. 8,277,510), which is a continuation of U.S.patent application Ser. No. 12/367,487, filed on Feb. 6, 2009 (now U.S.Pat. No. 8,088,163), which claims the benefit of priority from U.S.Provisional Patent Application Ser. Nos. 61/026,608 filed on Feb. 6,2008, the entire disclosures of which are hereby incorporated byreference in their entireties.

FIELD OF THE INVENTION

The present disclosure relates to the field of medical devices and isgenerally directed toward an implantable intervertebral fusion cage thatincludes a removable means for retaining material inside of the cageduring implantation.

BACKGROUND OF THE INVENTION

Spondylosyndesis, or spinal fusion, is a surgical technique used tocombine two or more vertebrae into a single, rigid working unit. This istypically achieved by introducing a supplementary bone tissue, such asan autograft or allograft, into the intervertebral space between twotarget vertebrae, at the location that is typically occupied by anintervertebral disc. The supplementary bone tissue is then used inconjunction with the patient's natural osteoblastic processes in orderto grow bone or osseous tissue between the two or more target vertebrae,which acts to fuse them together into the desired rigid unit. Thisprocedure is used primarily to eliminate pain that is caused by abnormalmotion of one or both of the target vertebrae; pain relief occurs byimmobilizing the vertebrae themselves and preventing the abnormalmotion. Alternatively, surgically implantable synthetic intervertebralfusion cages or devices may be used to perform spinal fusion procedures.

Surgically implantable intervertebral fusion cages are well known in theart and have been actively used to perform spinal fusion procedures formany years. Their use became popularized during the mid 1990's with theintroduction of the BAK Device from the Zimmer Inc., a specificintervertebral fusion cage that has been implanted worldwide more thanany other intervertebral fusion cage system. The BAK system is afenestrated, threaded, cylindrical, titanium alloy device that iscapable of being implanted into a patient as described above through ananterior or posterior approach, and is indicated for cervical and lumbarspinal surgery. The BAK system typifies a spinal fusion cage in that itis a highly fenestrated, hollow structure that will fit between twovertebrae at the location of the intervertebral disc.

When in use, a bone graft implant or synthetic fusion cage may be filledwith an orthopedic matrix containing additional fusion-promotingmaterial (FPM), for example including but not limited to calciumhydroxyapatite, bone morphogenic protein (BMP), demineralized bonematrix, collagen bone graft matrix (e.g. Formagraft®) and stem cellmaterial (e.g. Osteocel®) or other fusion-promoting substance placedwithin the spaces of the implant. The implant is then implanted into apatient at the desired location along that patient's spine where it willserve to promote bone growth and, ultimately, fusion of the two targetvertebrae. The fenestrations present in a typical intervertebral fusioncage allow the supplementary bone tissue to partially escape from thehollow interior of the cage and make sufficient contact with the targetvertebrae, thereby promoting fusion of the target vertebrae through thefusion cage itself. Unfortunately, the fenestrations, which areessential for the proper functioning of the intervertebral fusion cages,also present a major problem during surgical implantation of the cage inthat they are poor retainers of the FPM inside of the fusion cage duringimplantation because they cannot, and do not, retain the supplementarybone material inside of the fusion cage during implantation. Thesupplementary bone material typically used in conjunction with anintervertebral fusion cage may vary in viscosity, however one example ofa FPM typically used in conjunction with an intervertebral fusion cageis a viscous liquid that does not move as freely as water, however it issufficiently liquid in form so as to readily move from, or leak out of,the interior chamber of the fusion cage during implantation. Since thismaterial is intended to promote the formation of bony tissue inside of apatient's body, a leak of this material out of the fusion cage duringimplantation can lead to the creation of bony structures or osseoustissue at a location away from the surgical site and in locations thatcan cause severe medical complications for the patient, such asheterotopic bone formation, nerve compression, failure to properly healthe fusion area between the two target vertebrae, and numerous othercomplications.

It would be advantageous to provide tools suitable for use with asurgically implantable intervertebral fusion cage that is adapted toand/or capable of retaining the FPM inside of the cage duringimplantation and/or thereafter, until such time as it is desirous forthe FPM to come into contact with the target vertebrae, therebypreventing the material from flowing from, or moving out of, theinterior of the fusion cage during implantation and therebysignificantly reducing, if not eliminating, the risks noted above.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present disclosure provide a surgically implantableintervertebral fusion cage that is adapted to and/or capable ofretaining material, and particularly supplementary bone material, andmore particularly FPM, inside of the cage during implantation and/orthereafter, until such time as it is desirous for the supplementary bonematerial to come into contact with the target vertebrae, therebypreventing the material from flowing from, or moving out of, theinterior of the fusion cage during implantation and therebysignificantly reducing, if not eliminating, the risks associated withthe known devices, noted above. The present disclosure provides for thistype of fusion cage and tools for installing said cage, and thereforeaddresses and rectifies the problems associated with the prior art.Various embodiments of the present disclosure improve upon the knownimplantable intervertebral fusion cages and their use during surgicalimplantation. It is to be understood that the present disclosureincludes a variety of different versions or embodiments, and this BriefSummary of the Invention is not meant to be limiting or all-inclusive.This Summary provides some general descriptions of some of theembodiments, but may also include some more specific descriptions ofcertain embodiments.

Other embodiments of the present invention provide a means of freely andreadily removing the retaining means from the fusion cage after surgicalimplantation, and/or at any other desired time. In some embodiments, thepresent invention also includes methods of using and/or surgicallyimplanting fusion cages of the present invention. Although well suitedfor use in human patients, and although much of the discussion of thepresent invention is directed toward use in humans, advantages offeredby the present invention may be realized in the veterinary andscientific fields for the benefit and study of all types of animals andbiological systems. Additionally, although the fusion cages of thepresent invention are particularly well-suited for implantation into thespinal column between two target vertebrae, and although much of thediscussion of the present invention is directed toward their use inspinal applications, advantages offered by embodiments of the presentinvention may also be realized by implantation at other locations withina patient where the fusion of two or more bony structures may bedesired. As one of skill in the art will appreciate, the presentinvention has applications in the general field of skeletal repair andtreatment, with particular application to the treatment of spinalinjuries and diseases. It should be appreciated, however that theprinciples of the present invention can also find application in otherareas, specifically where there is a desire to constrain added fluidmaterial to particular regions. For example, the present invention findsapplication in methods where the objective is to confine added materialto predetermined areas of interest and to prohibit the undesiredtranslocation of such material until an operation is complete and/oruntil a predetermined later time.

Embodiments of the present disclosure provide for an implantableintervertebral fusion cage that is capable of retaining material, andparticularly supplementary bone material, within the interior chamber ofthe fusion cage during use, and particularly during surgicalimplantation, via the use of retaining means that serve to retain thesupplementary bone material inside of the fusion cage. Other embodimentsof the present disclosure provide a means of freely and readily removingthe retaining means from the fusion cage after surgical implantation,and/or at any other desired time. In some embodiments, the presentdisclosure also includes methods of using and/or surgically implantingfusion cages of the present disclosure.

Certain embodiments of the present disclosure are directed toward anovel, implantable intervertebral fusion cage that includes at least oneremovable shield or shim that is capable of retaining a surgicallyuseful material, such as a spinal fusion material, inside of the fusioncage during implantation and/or until the shield or shim is removed, andmethods of using the same. Further embodiments of the present disclosureare directed toward a novel distraction wedge that is configured toprepare the desired site of surgical implantation to receive the fusioncage of the present disclosure. Additional embodiments of the presentdisclosure are directed toward a novel impactor/holder that isconfigured to properly align the fusion cage of the present disclosureat the desired site of surgical implantation and to implant the fusioncage therein. Additionally, the present disclosure provides for methodsof surgically implanting a fusion cage into a patient, the methodsincluding a novel means of preparing the patient for implantation.

Further embodiments of the present disclosure provide for a distractionwedge that is capable of creating an opening between two desired targetstructures, such as adjacent bones and/or vertebrae, at a desiredsurgical site, such opening being capable of receiving any fusion cagetherein including, without limitation, the fusion cage of the presentdisclosure. In some embodiments, the distraction wedge has a headportion that is offset from the handle of the distraction wedge by anangle so that it may create the desired distraction or opening at thesurgical site without the need for the distraction wedge to be alignedwith the surgical site at a right angle.

Still other embodiments of the present disclosure provide for animpactor or holder that is capable of releasably securing embodiments ofthe spinal fusion cage to a distal end portion of the impactor or holderand delivering the fusion cage into a surgical site, while keeping thefusion cage secured to the distal end portion. The impactor or holder isalso configured to release the fusion cage once it is in place at thedesired surgical site. In some embodiments, the distal end portion ofthe impactor or holder is offset from the handle of the distracter orholder by an angle so that it may place the fusion cage into the desiredsurgical site without the need for the impactor or holder to be alignedwith the surgical site at a right angle. In some embodiments, theimpactor or holder is configured to deliver the fusion cage of thepresent disclosure into a desired surgical site and, after the fusioncage has been released from the distal end portion, to remove theretaining means from the fusion cage simultaneously with removal of theimpactor or holder from the surgical pathway.

Still other embodiments of the present disclosure provide for adistraction wedge and/or an impactor or holder having an exterior shaftand a distally-located rotating hinge that is configured to allow thehead portion of the distraction wedge and/or the distal end portion ofthe impactor or holder to rotate in at least one plane about an axis andthereby be offset from the handle of the distraction wedge and/or animpactor or holder, and from the exterior shaft, by any one of a numberof angles. The rotating hinge thus allows the head portion of thedistraction wedge and/or the distal end portion of the impactor orholder to be offset from the handle and from the exterior shaft by anangle so that they may be utilized as described herein without the needfor the handle of the distraction wedge and/or an impactor or holder orfor the exterior shaft to be aligned with the surgical site at a rightangle. In some embodiments, the angle of the head portion of thedistraction wedge and/or the distal end portion of the impactor orholder is determined by securing means located at the distal terminus ofthe external shaft, which are configured to lock the rotating hinge inplace, and thereby set a desired angle of use for the head portion ofthe distraction wedge and/or the distal end portion of the impactor orholder. In further embodiments, the distally-located rotating hinge isconfigured to allow for rotation of the head portion of the distractionwedge and/or the distal end portion of the impactor or holder in threedimensions around a single fixed point, in a manner substantiallysimilar to a wave platform shaker. In some embodiments, the retainingshims are capable of being removed from the fusion cage simultaneouslywith removal of the external shaft from the surgical pathway viasecuring means located along the exterior surface of the exterior shaft.

Although well suited for use in human patients, and although much of thediscussion of the present disclosure is directed toward use in humans,advantages offered by the present disclosure may be realized in theveterinary and scientific fields for the benefit and study of all typesof animals and biological systems. Additionally, although the fusioncages of the present disclosure are particularly well-suited forimplantation into the spinal column between two target vertebrae, andalthough much of the discussion of the present disclosure is directedtoward their use in spinal applications, advantages offered byembodiments of the present disclosure may also be realized byimplantation at other locations within a patient where the fusion of twoor more bony structures may be desired. As one of skill in the art willappreciate, the present disclosure has applications in the general fieldof skeletal repair and treatment, with particular application to thetreatment of spinal injuries and diseases. It should be appreciated,however that the principles of the present disclosure can also findapplication in other areas, specifically where there is a desire toconstrain added fluid material to particular regions. For example, thepresent disclosure finds application in methods where the objective isto confine added material to predetermined areas of interest and toprohibit the undesired translocation of such material until an operationis complete and/or until a predetermined later time.

As used herein, the term “shim” has a particular meaning within the art,but should also be understood to generally relate to any structure thatacts as a barrier to the undesired translocation of material, and inparticular, supplementary bone material and additional fusion-promotingmaterial (FPM), whether it be synthetic or otherwise, for exampleincluding but not limited to calcium hydroxyapatite, bone morphogenicprotein (BMP), demineralized bone matrix, collagen bone graft matrix(e.g. Formagraft®) and stem cell material (e.g. Osteocel®) or otherfusion-promoting substance placed within the spaces of the implant,whether it be synthetic or otherwise. Shims can therefore be constructedof any suitable material, including resorbable material ornon-absorbable material, dissolvable material, or other similar materialand may have various desired physical attributes specifically adaptedfor particular applications, for example, being flexible, subject tohaving its physical properties modified by application of light,chemicals, porous, colored, radiopaque, etc. Moreover, the use of theterm “cage” has a meaning understood in the art but may also beunderstood to generally relate to any geometrical structure, especiallyan enclosing structure, such as a box, rectangle, cylinder, or otherphysical configuration, that is adapted to constrain or confine materialfor desired periods of time within predetermined physical parameters.

In accordance with at least one embodiment of the present disclosure, animplantable intervertebral fusion cage is provided comprising a framewith at least one wall defining a hollow interior, the wall having atleast one, and in some embodiments a plurality, of openings orfenestrations through it allowing for fluid communication between thehollow interior and the exterior of the cage, the wall further includingat least one guiding structure located on an exterior surface of thewall that is configured to secure or hold one or more shields or shimsin place along the exterior surface of the wall so as to cover the atleast one, and In some embodiments a plurality, of openings. The guidingstructure or ridge is configured so as to allow the shim to be freelyremoved from and replaced onto the exterior surface of the wall. Whenthe shim is in place along the exterior of the cage and secured or heldin place by the guiding structure, thereby at least partially coveringthe at least one opening, the shim substantially prevents or precludesfluid communication between the hollow interior and the exterior of thecage. When the shim is removed from the guiding structure and is nolonger secured or held in place along the exterior surface of the wall,fluid communication is restored between the hollow interior and theexterior of the cage.

The intervertebral fusion cage of the present disclosure is typicallygeometrical in shape and/or design. In varying embodiments, the cage maybe configured and/or shaped as a box, square, rectangle, tube, disc,rod, cylinder, cone, and/or cage and/or may also take on any one or moreother shapes or configurations that may be useful in the fusion of twoadjacent bony structures within a patient. In some embodiments, theshape of the cage is identical in size and shape to the head portion ofa distraction wedge. Additionally, the intervertebral fusion cage of thepresent disclosure may be adapted to promote the fusion of the bonystructures when situated between two bony structures of interest, oradjacent to them.

In accordance with other aspects of the present disclosure, animplantable intervertebral fusion cage is provided comprising arectangular frame having a top wall, a bottom wall and four lateralwalls, each lateral wall being connected to the top wall at a top edgeand to the bottom wall at a bottom edge in such a way so as to form ahollow rectangular structure when the walls are interconnected. The topwall, bottom wall and the four lateral walls define a hollow interior ofthe cage when fully interconnected, and the top wall and the bottom walleach have at least one opening or fenestration through them allowing forfluid communication between the hollow interior and an exterior of thecage. The top wall and the bottom wall each further include at least oneguiding structure located on the exterior surface of the top wall andthe exterior surface of the bottom wall respectively, such guidingstructures being configured to hold a first shim in place along theexterior surface of the top wall and a second shim in place along theexterior surface of the bottom wall. The guiding structures areconfigured to allow the first shim and the second shim to be freelyremoved from, and replaced onto, the exterior surface of the top walland the exterior surface of the bottom wall, respectively. When thefirst shim is located along the exterior surface of the top wall and thesecond shim is in place along the exterior surface of the bottom wall ofthe cage, and held in place by a restraining means or preclusivebarrier, which in one embodiment is the guiding structures, the firstshim blocks the at least one opening or fenestration in the top wall ofthe case and the second shim blocks the at least one opening orfenestration in the bottom wall, thereby preventing fluid communicationbetween the hollow interior and the exterior of the cage. When eitherthe first shim or the second shim is, or both the first and second shimsare, removed from the at least one guiding structure, fluidcommunication is at least partially restored between the hollow interiorand the exterior of the cage. In some aspects of this embodiment of thepresent disclosure, the rectangular frame of the cage is square inshape.

In accordance with still other aspects of the present disclosure, animplantable intervertebral fusion cage is provided comprising acylindrical, tubular or conical frame having a main wall, a first endwall and a second end wall, each end wall being interconnected to themain wall so as to form a closed cylinder, tube or cone when the wallsare fully interconnected. The main wall, first end wall and second endwall, when fully interconnected, define a hollow interior of the cage.The main wall has at least one, and preferably a plurality, of openingsallowing for fluid communication between the hollow interior and theexterior of the cage. The main wall further includes at least oneguiding structure located on an exterior surface of the main wall thatis configured to secure or hold a shim in place along the exteriorsurface. The at least one guiding structure is configured to allow theshim to be freely removed from, and replaced onto, the exterior surfaceof the main wall. When the shim is located along the exterior surface ofthe main wall and secured or held in place by the at least one guidingstructure, the shim substantially covers or blocks the at least oneopening and substantially prevents fluid communication between thehollow interior and the exterior of the cage. When the shim is removedfrom the at least one guiding structure, fluid communication is at leastpartially restored between the hollow interior and the exterior of thecage.

In accordance with still other aspects of the present disclosure, amethod of surgically implanting an intervertebral fusion cage into adesired location within a patient is provided. In at least oneembodiment of these aspects of the present disclosure, the methodcomprises obtaining a cage having: (i) at least one wall defining ahollow interior of the cage, the wall having at least one opening orfenestration in it that allows for fluid communication between thehollow interior and the exterior of the cage; (ii) at least oneconstraining structure, such as a guiding structure, on an exteriorsurface of the wall that is configured to reversibly hold at least oneshim in place along the exterior surface of the wall, wherein the atleast one guiding structure is configured to allow the at least one shimto be removed from, and replaced onto, the exterior surface of the wall;and (iii) at least one removable shim. The method further includes thesurgeon or user preparing the cage for surgical implantation by fillingthe hollow interior with a material that is capable of fusing twovertebrae, or other bony structures, together and placing the at leastone shim along the exterior surface of the cage such that the at leastone shim is secured or held in place along the exterior surface by theat least one guiding structure and wherein the at least one shimsubstantially blocks the at least one opening or fenestration, therebysubstantially preventing fluid communication between the hollow interiorand the exterior of the cage and thereby retaining at least most of thematerial inside of the hollow interior. The method further includeslocating an appropriate site inside of the patient for implantation ofthe cage and creating a surgical opening in the patient that issufficient to accommodate the cage. After the opening is created, themethod includes surgically implanting the cage into the patient in sucha way that the fusion of the two vertebrae or other bony structures willoccur upon exposure to the material. Thereafter, the at least one shimis removed from contact with the guiding structure and thus the exteriorsurface of the wall, restoring fluid communication between the hollowinterior and the exterior of the cage and allowing the material to movefrom the hollow interior to the exterior of the cage. Once these tasksare completed, the method is concluded by closing the opening in thepatient.

In accordance with still other embodiments of the present disclosure, adevice is described that is directed to a spinal surgery graftcontainment device designed to contain the location of graft material insitu, or a method employing the same, including but not limited to adevice or method that employs generally planar elements disposed oneither side of a fusion implant having one or more apertures thereinthat can receive graft material.

In accordance with still other aspects of the present disclosure, amethod of surgically implanting an intervertebral fusion cage into adesired location within a patient is provided. In at least oneembodiment of these aspects of the present disclosure, the methodcomprises obtaining a cage having: (i) at least one wall defining ahollow interior of the cage, the wall having at least one opening orfenestration in it that allows for fluid communication between thehollow interior and the exterior of the cage; (ii) at least oneconstraining structure, such as a guiding structure, on an exteriorsurface of the wall that is configured to reversibly hold at least oneshim in place along the exterior surface of the wall, wherein the atleast one guiding structure is configured to allow the at least one shimto be removed from, and replaced onto, the exterior surface of the wall;(iii) at least one removable shim; and (iv) means for receiving asecuring element capable of securing the cage to a distal end portion ofan impactor or holder. The method also includes the surgeon or userpreparing the cage for surgical implantation by filling the hollowinterior with a material that is capable of fusing two vertebrae, orother bony structures, together and placing the at least one shim alongthe exterior surface of the cage such that the at least one shim issecured or held in place along the exterior surface by the at least oneguiding structure and wherein the at least one shim substantially blocksthe at least one opening or fenestration, thereby substantiallypreventing fluid communication between the hollow interior and theexterior of the cage and thereby retaining at least most of the materialinside of the hollow interior. The method further includes locating anappropriate site inside of the patient for implantation of the cage,positioning the patient so as to obtain the desired amount of exposureof the desired surgical site, and creating a surgical opening in thepatient that exposes the desired surgical site and that is sufficient toaccommodate the cage. Once the opening is created, the method furtherincludes generating a sufficient amount of distraction, or an opening ofdesired size and shape, at the surgical site by inserting a distractionwedge into the patient, contacting the distraction wedge with the tissueto be opened, and moving the distraction wedge into the tissue to beopened until the desired shape and depth of distraction, or opening, iscreated in the tissue to be opened. Thereafter, the method furtherincludes surgically implanting the cage into the patient in such a waythat the fusion of the two vertebrae or other bony structures will occurupon exposure to the material by securing the cage to a distal endportion of an impactor or holder, moving the cage and impactor or holderinto the surgical opening and contacting the cage with the site ofsurgical implantation, and moving the cage into the surgical site.Thereafter, the cage is selectively released from the distal end portionof the impactor or holder and the impactor is removed from the surgicalopening. In some embodiments of this method, the at least one shim isremoved from contact with the guiding structure and thus the exteriorsurface of the wall, restoring fluid communication between the hollowinterior and the exterior of the cage and allowing the material to movefrom the hollow interior to the exterior of the cage, simultaneouslywith the removal of the impactor or holder from the surgical opening. Inother embodiments, the shim is removed after the impactor is removedfrom the surgical opening. Once these tasks are completed, the method isconcluded by closing the opening in the patient.

Further aspects of the present disclosure include methods of preparing apatient for surgical implantation of a fusion cage, including theintervertebral fusion cage of the present disclosure. In someembodiments and referring specifically now to FIG. 12A, the patient isplaced on his or her back, so that the surgical site has anteriorexposure, providing access to the implant site through the abdomen. Inyet another embodiment, the patient is placed on his or her front orabdomen, so that the implant site has posterior exposure, providingaccess to the implant site through the More preferably and referringspecifically now to FIG. 12B, and in other embodiments, the patient islaterally positioned, or placed on his or her side, so that the portionof the intervertebral space into which a fusion cage is to be implantedis closer in proximity to the health care provider than if the patientwere to be placed on his or her other side. The patient is thenmaximally bent laterally so that the side that is closer in proximity tothe health care provider is maximally arched, with the other side beingminimally arched. In this position, the health care provider uses alateral or flank approach to access the implant site. In this way, theintervertebral space of interest is presented in as open a configurationas possible, thereby creating better access to the area of interest anddecreasing the chance of creating surgical complications that can occurwhen the intervertebral space is not maximally presented as describedabove. This lateral or flank approach combined with certain aspects ofthe tool of the present disclosure, including the adjustability of thehead portion of the tool allows a user or health care provider to gainaccess to and treat multiple vertebrae, implant sites, and surgicalsites that were traditionally inaccessible with a lateral approach.

In one aspect of the present disclosure, a tool is provided fordelivering or placing an intervertebral cage, graft, distraction wedgeor other device into an implant or surgical site. The tool has agenerally syringe-shaped handle and body, with, on the handle, a meansfor communicating with the distal end of the body. In one embodiment,the means for communication comprises a component manipulated by asurgeon's thumb during an operation. Such means may comprise a trackball, a rotating member, a lever, an electronically controlled signal, abutton, or another structural feature that provides desired movement atthe opposite end of the tool. In one such embodiment, a thumbscrew orthumbwheel is at the proximal end of the handle, and a hollow,cylindrical body is attached to the handle whereby the thumbscrew canrotatably communicate with the distal end of the body via a cable, shaftor other rotating means. The tool has a hinge on the distal end of thebody that rotates in at least one axis that is substantiallyperpendicular to the axis of the cylindrical body, and thatinterconnects the body to the head of the tool. The hinge on the distalend provides articulation of the head with respect to the body of thetool. It should be understood that the hinge may be any rotating memberthat allows rotation in at least one plane between two parts.

The cylindrical body has at least one fastener, at a point between theproximal handle and the distal rotating member, that is capable ofsecuring a tab, tether or other apparatus to the body of the tool. Thefastener may be, for example, a clamp, a clip, a cam-lock or othersimilar device. In yet another aspect of the present disclosure, thisfastener may be affixed, or it may be drawn towards the proximal handle,or it may be wound in order to draw in the tab, tether or otherapparatus. Devices that may draw in the tab, tether or other apparatusare well known in the art. Incorporated by reference herein in theirentireties are the following U.S. patents and publications generallydirected to reels and cam-locking devices that may be used to draw inthe tab, tether or other apparatus of the present disclosure: U.S. Pat.No. 6,149,096 to Hartley, U.S. Pat. No. 4,039,156 to Abraham, U.S. Pat.No. 3,741,496 to Beller, U.S. Pat. No. 3,836,092 to Hull, U.S. Pat. No.5,058,823 to Emura, U.S. Pat. No. 5,333,812 to Sato and U.S. Pat. No.3,697,011 to Christensen.

The hinge on the distal end is capable of selectively locking (e.g., bya pin) the head into a particular position, e.g. so that a desired angleis created between the head and the body of the tool. The means forcommunication itself can be locked to alternatively achieve thisobjective. In one embodiment, when the rotating member is in an unlockedmode, the member is free to rotate in at least one plane. The selectivelocking mechanism can be remotely accessed by a user of the tool at theproximal end of the handle by, for example, an external shaft thatcommunicates with the locking mechanism of the rotating member on thedistal end of the body.

The head of the tool has a reversible fastening device (e.g., a threadedmember) that is in rotatable communication with the means forcommunicating, for example, a thumbscrew, via the cable, shaft or otherrotating means in the body. In one embodiment, the fastening device isused, by way of the thumbscrew, to secure components such as anintervertebral cage, graft or distraction wedge, that have correspondingand complementary fastening locations, to the head of the tool. Once thecomponent is secured to the head of the tool, a tab, tether or otherapparatus may be secured to the body of the tool using the at least onefastener. This assembly (See, e.g., FIG. 15) is now generally preparedfor implantation or insertion into an implant site.

This tool (e.g. as pictured in FIGS. 14A and 14B) is preferably usedwith an implant device or graft that may need to be positioned into ajoint space and thereafter released. Preferably, the tool is used toposition the cage comprising removable veneers as described herein. Thistool provides articulation of the head, and therefore the implant orgraft, which allows a user to better position the implant or graft intothe surgical site. This tool is also preferably used to attach tools tothe head (e.g., a distraction wedge), whose angle with the body andhandle may need to be periodically adjusted during a procedure. Inparticular, this tool is more preferably used with an intervertebralfusion device that has at least one shim or veneer with a tab or tether.The shim or veneer is used to cover a hole, aperture or fenestrationthat may be present in a wall of the fusion device. The tool is able tofasten to the fusion device, and the securing means is able to securethe tabs or tethers of the shims of the fusion device to the fastener onthe body of the tool. In particular, a shim or veneer can be operativelyassociated with the tool as follows:

In use, once the fusion device is implanted into the desiredimplantation site, the user is able to engage the reversible fasteningdevice via the means for communication, e.g. the thumbscrew, to releasethe fusion cage, and remove the tool from the surgical site, which willsimultaneously remove the shim or veneer via the tab or tether. Priorart tools and cages are not designed to permit the insertion, as well asdisengagement, of shims, veneers or the like from a surgical site uponcompletion of a fusion operation. In another more preferable use of thetool, the fastener on the cylindrical body is first used to retract,draw or wind the tab, tether or other apparatus to remove the shim orveneer to which the tab, tether or other apparatus is attached. Once theshim or veneer to which the tab, tether or other apparatus is attachedis removed from the fusion device, the fusion device is selectivelyreleased by the user. The user may then remove the tool from the implantor surgical site, with the result being that only the implant device orgraft remains in the patient, and the tool along with the shim or veneerand the associated tab, tether or apparatus is removed from the surgicalsite. Thus, using the present tool, a surgeon is able to ensure that thefusion device remains in its intended location within the patient as theshim or veneer is drawn from the surgical site and that any forceimparted by the shim or veneer as it is being drawn does not cause anundue shift of the fusion device. Certain aspects of the presentinvention are thus directed to the use of a tool that facilitates thedesired positioning of a cage, particularly one that comprises removableportions, such as veneers or shims, in such a manner that the desiredposition of the cage is not substantially altered when the removableportions are removed from the operation site. Prior art tools are mainlydesigned for the implantation and positioning of cages, but are notdesigned or suited for the selective removal of particular portions ofnew cages, such as the one described herein. Further, means forselective removal of particular portions of new cages, as describedherein, are affixed to the body of the tool to provide reliable andconsistent removal of the particular portions.

Yet another aspect of the present disclosure is that theimpaction/distractor system can be variably angled to allow for avariety of insertion angles. A ratcheting adapter can be fitted to allowfor this application. Furthermore, the present invention can be used inveterinary conditions, in the thoracic spine or can be used forinsertion of a laterally based disk replacement.

Yet another aspect of the present disclosure is that it can be used asan intervention for the approach to the traumatically damaged spine,spinal deformity or reconstruction for tumor destruction. Angled cagescan be applied to correct deformity at the disk space or replacevertebrae that require removal.

Incorporated by reference in their entireties are the following U.S.patents and publications directed generally to methods and apparatusrelated to spinal procedures, thus providing written description supportfor various aspects of the present disclosure. The U.S. patents andpublications fully incorporated herein by reference are as follows: U.S.Pat. No. 7,481,766 to Lee et al., U.S. Pat. No. 7,442,208 to Mathieu etal., U.S. Pat. No. 7,429,270 to Baumgartner et al., U.S. Pat. No.7,371,239 to Dec et al., U.S. Pat. No. 7,361,178 to Hearn et al., U.S.Pat. No. 7,357,804 to Binder et al., U.S. Pat. No. 7,238,203 to Bagga etal., U.S. Pat. No. 7,223,292 to Messerli et al., U.S. Pat. No. 6,974,480to Messerli et al., U.S. Pat. No. 6,730,125 to Lin, U.S. Pat. No.6,673,113 to Ralph et al., U.S. Pat. No. 6,500,206 to Bryan, U.S. Pat.No. 6,454,806 to Cohen et al., U.S. Pat. No. 6,245,108 to Biscup, U.S.Pat. No. 6,146,420 to McKay, U.S. Pat. No. 5,782,919 to Zdeblick et al.,U.S. Pat. No. 5,541,191 to Lahille et al., U.S. Pat. No. 5,055,104 toRay, U.S. Pat. No. 5,688,285 to Yamada, U.S. Pat. No. 5,290,295 toQuerals, U.S. Patent Publication 2008/0033440 to Moskowitz et al., U.S.Patent Publication 2007/088007 to Burkus et al., U.S. Patent Publication2007/0208423 to Messerli et al., U.S. Patent Publication 2004/0034430 toFalahee, and U.S. Patent Publication 2004/0153158 to Errico et al. andU.S. application Ser. No. 11/093,409 filed Mar. 29, 2005.

Though the description of the disclosure includes descriptions of one ormore embodiments and certain variations and modifications, othervariations and modifications are to be understood as being within thescope of the invention, e.g., as may be within the skill and knowledgeof those in the art, after understanding the present disclosure. Theinventor intends to obtain rights which include alternative embodimentsto the extent permitted, including alternate, interchangeable and/orequivalent structures, functions, ranges or steps to those explicitlydescribed and/or claimed, whether or not such alternate, interchangeableand/or equivalent structures, functions, ranges or steps are explicitlydisclosed herein, and without intending to publicly dedicate anypatentable subject matter.

Various embodiments of the present disclosure are set forth in theattached figures and in the Detailed Description as provided herein andas embodied and/or exemplified by the claims. It should be understood,however, that this Summary does not contain all of the aspects andembodiments of the present invention, is not meant to be limiting orrestrictive in any manner, and that the invention as disclosed herein isand will be understood by those of ordinary skill in the art toencompass obvious improvements and modifications thereto and thoseimprovements and modification that are within the skill and knowledge ofthose in the art.

Additional advantages of the present invention will become readilyapparent from the following discussion, particularly when taken togetherwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many advantages of the present invention will be apparent to thoseskilled in the art with a reading of this specification in conjunctionwith the attached drawings, wherein:

FIG. 1A shows a known rectangular intervertebral fusion cage present inthe prior art;

FIG. 1B shows a known cylindrical intervertebral fusion cage present inthe prior art;

FIGS. 2A and 2B show two embodiments of a guiding structure according toat least some embodiments of the present disclosure;

FIGS. 3A and 3B show two additional embodiments of a guiding structureaccording to at least some embodiments of the present disclosure;

FIG. 4 shows an intervertebral cage according to at least someembodiments of the present disclosure with a removable shim being placedalong an external surface of the cage;

FIG. 5A shows an embodiment of the removable shim according to at leastsome embodiments of the present disclosure;

FIG. 5B shows a close up of a removable shim in contact with an externalsurface of a cage and held in place by a guiding structure according toat least some embodiments of the present disclosure;

FIG. 6 shows an end view of a tubular or cylindrical cage with tworemovable shims in contact with an external surface of the cage and heldin place by two guiding structures according to at least someembodiments of the present disclosure;

FIGS. 7A, 7B and 7C show two views of an embodiment of a cage having twoguiding structures on a top external surface and two guiding structureson a bottom external surface of the cage according to at least someembodiments of the present disclosure;

FIGS. 8A and 8B show two views of an embodiment of a shim according toat least some embodiments of the present disclosure;

FIG. 9 is an end view of the cage of FIG. 3B according to at least someembodiments of the present disclosure;

FIGS. 10A and 10B show two views of an embodiment of embodiment of ashim according to at least some embodiments of the present disclosure;

FIGS. 11A and 11B show two views of a distraction wedge according to atleast some embodiments of the present disclosure;

FIG. 12A is a side view of a posteriorly positioned patient according toat least some embodiments of the present disclosure, in the depictedscene, a distraction wedge according to at least some embodiments of thepresent disclosure is shown in place between vertebrae L4 and L5;

FIG. 12B is a side view of a laterally positioned patient who ismaximally bent laterally according to at least some embodiments of thepresent disclosure, in the depicted scene, a distraction wedge accordingto at least some embodiments of the present disclosure is shown in placebetween vertebrae as shown;

FIGS. 13A and 13B show two views of an impactor or holder according toat least some embodiments of the present disclosure; and

FIGS. 14A and 14B show two views of an impactor or holder having anexterior shaft and a distally-located rotating hinge according to atleast some embodiments of the present disclosure;

FIG. 15 shows a view of an impactor or holder having an exterior shaftand a distally located rotating hinge according to at least someembodiments of the present disclosure, and a fusion cage, graft or otherdevice secured to the distal end of the impactor or holder.

FIGS. 16A and 16B show two views of a cage according to at least someembodiments of the present disclosure;

FIGS. 17A and 17B show two views of a veneer according to at least someembodiments of the present disclosure;

FIGS. 18A and 18B show two views of a portion of a cage and a portion ofa veneer according to at least some embodiments of the presentdisclosure;

FIGS. 19A and 19B show two views of a ridge portion of a cage accordingto at least some embodiments of the present disclosure;

FIGS. 20A and 20B show two views of a cage according to at least someembodiments of the present disclosure;

FIGS. 21A, 21B and 21C show three views of a cage and a veneer accordingto various embodiments of the present disclosure; and

FIGS. 22A and 22B show two views of an implantable cage according tovarious embodiments of the present disclosure.

The drawings are not necessarily to scale and the drawings may includeexaggerated features for purposes of clarity.

DETAILED DESCRIPTION

This Detailed Description is being provided with simultaneous referenceto all of the attached figures. The present disclosure provides for animplantable intervertebral fusion cage that is capable of retainingmaterial, and particularly supplementary bone material and moreparticularly FPM, within an interior chamber of the fusion cage duringuse and/or during surgical implantation via the use of retaining meansthat serve to hold the supplementary bone material or FPM inside of ahollow chamber of the fusion cage. The present disclosure also providesfor at least one means of removing the retaining means from theimplantable fusion cage upon implantation of the cage, or at any otherdesired time. The present disclosure therefore improves upon all of theknown surgically implantable intervertebral fusion cages present in theprior art by including at least one shield or shim that is held along atleast one exterior surface of an intervertebral fusion cage and thatserves to at least partially, preferably at least substantially, andeven more preferably completely, block the movement of material from thehollow interior chamber of the cage to the exterior of the cage untilsuch time as it is desirous for such movement to occur. The at least oneshim is freely removable and may be put into place and removed from thecage numerous times with no loss of function. The at least one shim isheld in place along the exterior of the intervertebral fusion cage by atleast one guiding structure, located along an external surface of thecage, that overlaps with at least a portion of at least one edge of theshim so as to secure the shim in place on the external surface andprevent the shim from moving or migrating during use and/or implantationof the cage. The contact of the at least one guiding structure with theat least one shim is therefore sufficient to hold the shim in placeduring use and/or implantation of the cage and to prevent fluidcommunication between the interior and the exterior of the cage, but isalso operable to allow the shim to be freely removed from, and/orreplaced onto, the cage. It is intended in some embodiments that theshim of the present disclosure be freely removable from the guidingstructure by the user or health care provider implanting the cage, butthat the at least one shim be held in place by the at least one guidingstructure sufficiently tightly so as to prevent any unintended movementor shifting during surgical implantation of the cage and thereforeprevent fluid communication between the hollow interior chamber and theexterior of the cage. One having skill in the art will appreciate thatthe shim may be a film, a laminate, a veneer, a wedge, a section, asegment, a shim, a plug, a coating, a surface, a plate and a cover thatis operable to engage at least one exterior surface of an intervertebralfusion cage, and operable to at least partially, preferably at leastsubstantially, and more preferably completely, block the movement ofmaterial from the hollow interior of the cage to the exterior of thecage. For ease of explanation, and without meaning to unduly restrictthe invention, throughout this description the use of a singular term,such as shim, veneer, etc. will be generally understood to refer to oneof the several embodiments of the invention.

Information relevant to the current state of the art as it applies tosurgically implantable intervertebral fusion cages, including usefulwritten, enabling descriptions of how to make and use variouscomponents, can be found in the following U.S. patents and U.S. patentPublications, the entire contents of which are incorporated herein bythis reference: U.S. Pat. No. 5,653,763 to Errico et al.; U.S. Pat. No.5,665,122 to Kambin; U.S. Pat. No. 5,888,228 to Knothe et al.; U.S. Pat.No. 6,090,143 to Meriwether et al.; U.S. Pat. No. 6,159,245 toMeriwether et al.; U.S. Pat. No. 6,648,915 to Sazy; U.S. Pat. No.6,699,288 to Moret; U.S. Pat. No. 7,094,257 to Mujwid et al.; U.S. Pat.No. 7,135,043 to Nakahara et al.; U.S. Pat. No. 7,232,463 to Falahee;U.S. Patent Application Publication No. 2003/0083748 to Lee et al.; U.S.Patent Application Publication No. 2004/0143330 to Sazy; U.S. PatentApplication Publication No. 2004/0162618 to Mujwid et al.; U.S. PatentApplication Publication No. 2005/0149192 to Zucherman et al.; U.S.Patent Application Publication No. 2005/0149193 to Zucherman et al.;U.S. Patent Application Publication No. 2005/0283236 to Razian; and U.S.Patent Application Publication No. 2007/0270951 to Davis et al.

In accordance with at least some aspects of at least one embodiment ofthe present disclosure, a surgically implantable intervertebral fusioncage is provided. The fusion cage includes a frame with at least onewall defining a hollow interior within the frame, the at least one wallhaving sufficient structural stability so as to withstand surgicalimplantation in a patient and to withstand the physical stresses that itwill encounter after implantation as the patient moves. Although notrequired in the present disclosure, in some embodiments, the walls thatcomprise the cage will be generally planar elements. Generally planar ismeant to mean relating to, or lying in a plane. A plane is athree-dimensional surface where, for any two points, a straight linejoining the two points will lie wholly inside the surface. One havingskill in the art will appreciate that the generally planar elements maybe any structure or device that is capable of spanning two lines inspace, and may be made of a material and configured to be structurallycapable of resisting deformation substantial plastic deformation underforces including stress, strain and compression. A shim of certainembodiments of the invention may have one or more planar elements,especially when a corresponding cage structure has more than one surfaceto be contacted with a shim While it is not required for purposes of thepresent disclosure, in some embodiments the cage will have a pluralityof walls defining the hollow interior such that the cage may take theshape of a rectangle, square, box, tube, cylinder, cone, polygon, orother shape suitable for implantation into a patient. The at least onewall has at least one, and in some embodiments a plurality, of openings,apertures or fenestrations through it that provide open access to thehollow interior of the fusion cage and that allow for fluidcommunication between the hollow interior of the cage and the exteriorof the cage. These openings, apertures and/or fenestrations serve thepurpose of allowing a supplementary bone material, such as a bonegrafting material, or FPM, which is inserted into the hollow interiorprior to surgical implantation, to leave the hollow interior of thecage, make contact with the desired vertebrae or other bony structures,and promote the fusion of the two vertebrae or other bony structures.Further, one having skill in the art will appreciate that as usedherein, an opening, aperture and/or fenestration through the wall may bea perforation, a slot, a gap, a hole, a cavity, a notch or other breachin the wall that enables fluid communication between the hollow interiorof the cage and the exterior of the cage. Further, the openings,apertures and/or fenestrations need not necessarily permit anunobstructed straight path from a point in the hollow interior of thecage to a point in the exterior of the cage (e.g., the wall may becomprised of a plurality of layers, wherein each layer has at least oneopening aperture and/or fenestration, and the openings, apertures and/orfenestrations are offset and non-overlapping).

The at least one wall further includes at least one guiding structurelocated on an exterior surface of the at least one wall such that the atleast one guiding structure is located on an exterior surface of thecage relative to the hollow interior. The at least one guiding structurefunctions to hold at least one shim to the exterior surface of the cageand is preferably configured so as to hold the shim against the exteriorsurface of the cage sufficiently tightly so as to at least substantiallyblock the fluid communication between the hollow interior of the cageand the exterior of the cage while the shim is in place. The at leastone guiding structure is also configured so as to allow the shim to beremoved at any time it is desirous for the user to do so, such as aftersurgical implantation. In some embodiments, when the shim is held inplace along the exterior surface by the at least one guiding structure,the shim serves to at least partially, and preferably completely, coveror block the at least one opening or fenestration in the wall, thuspreventing fluid communication between the hollow interior and theexterior of the cage and thereby preventing the movement of material outof the hollow interior. Therefore, when the shim is removed from contactwith the guiding structure and the exterior surface of the cage, fluidcommunication is restored between the hollow interior and the exteriorof the cage and material will be free to move from the hollow interiorto the exterior of the cage.

In another embodiment of the present disclosure, the at least one wallmay be comprised of a plurality of generally parallel, planar walls,each wall in the plurality having at least one opening, aperture and/orfenestration. The resulting structure would have at least one interiorwall and at least one exterior wall creating a substantially planarspace between the two walls. The substantially planar space may beconfigured to hold at least one shim against one of the exterior surfaceof the inner wall and the interior surface of the outer wall. Thesubstantially planar space and the shim are preferably configured so asto hold the shim against one of the inner and outer wall sufficientlytightly so as to at least substantially block the fluid communicationbetween the hollow interior of the cage and the exterior of the cagewhile the shim is in place. As in the foregoing paragraph, thesubstantially planar space and the shim are configured so as to allowthe shim to be removed at any time it is desirous for the user to do so,such as after surgical implantation.

In accordance with at least some aspects of at least one embodiment ofthe present disclosure, a surgically implantable intervertebral fusioncage is provided, the cage having a hollow frame that is substantiallyrectangular or square in shape. For purposes of illustration, andwithout wishing to be held to any one embodiment, the following U.S.patents and U.S. patent Publications are incorporated herein by thisreference in order to provide an illustrative and enabling disclosureand general description of an intervertebral fusion cage that issubstantially rectangular or square in shape: U.S. Pat. No. 5,653,763 toErrico et al.; U.S. Pat. No. 5,665,122 to Kambin; U.S. Pat. No.5,888,228 to Knothe et al.; U.S. Pat. No. 6,090,143 to Meriwether etal.; U.S. Pat. No. 6,159,245 to Meriwether et al.; U.S. Pat. No.6,699,288 to Moret; U.S. Pat. No. 7,094,257 to Mujwid et al.; U.S. Pat.No. 7,135,043 to Nakahara et al.; U.S. Pat. No. 7,232,463 to Falahee;U.S. Patent Application Publication No. 2003/0083748 to Lee et al.; U.S.Patent Application Publication No. 2004/0162618 to Mujwid et al.; andU.S. Patent Application Publication No. 2005/0283236 to Razian. Each ofthe foregoing discloses cages that have the same basic square orrectangular construction and, for the sake of simplicity, will becollectively referred to herein as having a top wall, a bottom wall andfour lateral walls which collectively form the shape of a rectangle orsquare in that each lateral wall is connected to a single edge of thetop wall at a top edge of the lateral wall and the bottom edge of thelateral wall is connected to a single edge of the bottom wall in such away that the top wall, bottom wall and four lateral walls, when fullyinterconnected, create a shape that is substantially rectangular orsquare-shaped and also define a hollow interior to the cage. In someembodiments, additional walls may be present, for example within theinterior chamber of the cage in order to create at least two separatehollow interior chambers within the cage and the guiding structures andshims of the present disclosure will operate identically with theseembodiments with no loss of function whatsoever.

The intervertebral fusion cage has a height ranging from about 8 mm toabout 18 mm, a width ranging from about 10 mm to about 12 mm, and alength ranging from about 18 mm to about 55 mm. Thus, both the top andbottom walls preferably have a length that ranges from about 18 mm toabout 40 mm and a width ranging from about 10 mm to about 12 mm, andeach of the lateral walls have a length that ranges from about 18 mm toabout 40 mm and a width ranging from about 8 mm to about 18 mm. Whenfully constructed, the substantially rectangular or square shaped cageshave a flat profile such that they are longer and wider than they aretall, making the largest points of contact of the cage with the targetvertebrae the exterior surface of the top wall and the exterior surfaceof the bottom wall. The lateral walls may also make contact with thetarget vertebrae, though it is preferable that the major points ofcontact with the target vertebrae will occur via the exterior surface ofthe top wall and the exterior surface of the bottom wall.

Both the top wall and the bottom wall have at least one opening orfenestration, and preferably a plurality of openings or fenestrations,that provide a location, or locations, where material, that is placed orstored inside of the hollow interior, may freely move from the hollowinterior to the exterior of the cage. The at least one opening orfenestration, and preferably a plurality of openings or fenestrations,thus allow for fluid communication between the hollow interior of thecage and the outside of the cage. The purpose of these openings orfenestrations is to provide a means by which a portion of a material,such as supplementary bone material or bone grafting material, that isplaced inside of the hollow interior of the cage prior to implantation,may escape from the hollow interior and make contact with the targetvertebrae, at the top of the cage and at the bottom of the cage, whileretaining a portion of the material inside of the hollow interior. Inthis way, the material makes contact with one of the target vertebrae atthe exterior surface of the top wall of the cage and makes contact withanother of the target vertebrae at the exterior surface of the bottomwall of the cage, while at the same time there is sufficient materialremaining inside of the hollow interior so as to promote the fusion ofthe target vertebrae by the generation of bony or osseous tissue throughand around the fusion cage.

Additionally, at least one of the exterior surface of the top wall orthe exterior surface of the bottom wall has at least one, and in someembodiments two, three, or more, guiding structures located on it, whichis configured to hold a shield or shim in place along the exteriorsurface of the wall in question. In some embodiments, the guidingstructure is present on three, and even more preferably two, of theedges of the exterior surface such that the shield or shim is held inplace by the guiding structure along at least two, and in someembodiments three, sides of the exterior surface of the wall inquestion. In some embodiments, the external surface has a plurality ofguiding structures located on it and there may be two guiding structuresalong two opposing edges of the external surface such that the shim isheld in place along two opposing edges of the external surface, or theremay be three separate guiding structures located along the same edges ofthe exterior surface as previously described for the continuous guidingstructure, such that the shim is held in place along three sides bythree separate guiding structures. Referring now specifically to FIG. 4,a shim 404 is shown that is held in place by three guiding structures408 along the exterior surface of a wall. In still other embodiments andreferring specifically to FIG. 3B, there are a plurality of guidingstructures 316 holding the shim in place, some located along the edgesof the external surface as previously described and at least one locatedin a belt-like fashion across the external surface and spanning thedistance from one wall to an opposing wall (e.g., from the top wall tothe bottom wall) such that the shim is positioned between the belt-likeguiding structure and the exterior surface of the wall, and is held inplace along the exterior surface by the belt-like guiding structureaccordingly. Referring specifically now to FIG. 9, a side aspect view ofa cage is shown illustrating a belt ridge and the slot created by theridge through which the shim is held in place. In those embodimentsusing belt-like guiding structures, it is preferable for a plurality ofbelt-like guiding structures 316 to be present.

In some embodiments, it is preferable for at least one guiding structureto be located along both the exterior surface of the top wall and theexterior surface of the bottom wall so that a first shim may be held inplace by at least one guiding structure along the external surface ofthe top wall and a second shim may be held in place by at least oneguiding structure along the external surface of the bottom wall. Asmentioned above, the top and bottom walls have the at least one, andpreferably a plurality of, openings or fenestrations through them thatallow for the movement of material out of the hollow interior and towardthe target vertebrae. Therefore, when a first shim is held in place byat least one guiding structure along the exterior surface of the topwall and a second shim is held in place by at least one guidingstructure along the exterior surface of the bottom wall, the first shimand the second shim at least partially block or cover, and preferablycompletely block or cover, the at least one opening or fenestrationlocated along and through the top and bottom walls. When the at leastone opening or fenestration is covered or blocked in this manner, theshims serve to prevent the movement of material, such as supplementarybone material or bone grafting material, from the hollow interior to theexterior of the cage. The shims thus serve to prevent or block the fluidcommunication that would otherwise exist between the hollow interior andthe exterior of the cage. Therefore, when either the first shim or thesecond shim is, or both the first and second shims are, removed fromcontact with the guiding structures located along the external surfacesof the top wall and the bottom wall, fluid communication is restoredbetween the hollow interior and the exterior of the cage and thematerial may move from the hollow interior through the at least oneopening or fenestration to the outside of the cage.

It is also preferable for the at least one guiding structure to beconfigured to hold or retain the shim(s) in place along the externalsurface in question sufficiently tightly so as to prevent the movementof material from the hollow interior to the outside of the cage. It isthus another aspect of the present disclosure for the at least oneguiding structure to hold the shim(s) in place along, and in directcontact with, the external surface of the wall in question so that theshim(s) lies flat, without any wrinkles or gaps, and such that theshim(s) is held in contact with the external surface so as to preventthe movement of a substantial amount of a free flowing fluid, such aswater, from the hollow interior to the outside of the cage, and tocompletely prevent the movement of a more viscous material, such as asupplementary bone material or bone grafting material, from the hollowinterior to the outside of the cage. It is also an aspect of the presentdisclosure for the at least one guiding structure to be configured toallow the shim(s) to be freely removable from the external surface ofthe wall in question and replaceable onto the external surface of thewall in question numerous times with no loss of function whatsoever. Itis therefore preferable for the at least one guiding structure to beconfigured so as to allow the shim(s) to move into and out of placealong the external surface a plurality of times and to still hold theshim(s) in place sufficiently snugly to at least substantially preventthe movement of a viscous material from the hollow interior to theoutside of the cage.

The at least one guiding structure may be configured in any number ofmanners that will allow the guiding structure to hold the shim snugly tothe external surface and to allow for the free removal and replacementof the shim numerous times with no loss in function. In some embodimentsand referring specifically to FIG. 2A, the guiding structure 208 is asingle projection that extends outward from the external surface of thewall in question at an angle θ 210 such that the shim slides under theguiding structure and is held in place until such time as the shim isremoved from under the guiding structure 208. In these embodiments, theguiding structure 208 extends outward from the external surface at anangle that may be configured to fit a specific shim, and/or at an angleθ 210 ranging from about zero degrees to about 45 degrees, or morepreferably from about 15 degrees to about 35 degrees. In theseembodiments, the shim is held in place under the guiding structure 208strictly by the angle 210 of the guiding structure, which makes contactwith the shim along the underside of the guiding structure and holds theshim snugly to the external surface or cage wall 204.

In other embodiments and referring specifically to FIGS. 2B and 5B, theguiding structure is comprised of a projection of the following generalconfiguration:

-   -   ┌

In these embodiments, the bottom portion 212 of the guiding structure220 shown above projects straight up and outward from the cage wall 204or external surface 512 of the cage, and the upper portion, or overhang216, extends perpendicularly to the bottom portion 212 and projectstoward the center of the external surface in such a way so that the shimslides under the overhang 216 of the guiding structure 220 and is heldin place by the guiding structure by making contact with the bottomportion 212, overhang 216 and external surface 204 of the cage. Theoverhang portion 216 of this embodiment may vary in angle, though it ispreferable that the overhang portion 216 be at a 90 degree angle fromthe bottom portion 212.

In still other embodiments and referring specifically to FIG. 3A, theguiding structure 314 may be configured to secure a shim on two sides.The guiding structure of these embodiments has the following generalconfiguration:

-   -   T

In these embodiments, the bottom portion 308 of the guiding structure314 shown above projects straight up and outward from the externalsurface 304 and the upper portion, or crossbar 312, projects outwardfrom the bottom portion in two directions, so that a shim can slideunder either side of the crossbar 312 of the guiding structure 314 andbe held in place by the crossbar 312. It is preferable for the crossbar312 portion of these embodiments to be at a 90 degree angle, orperpendicular, from the bottom portion 308. These embodiments of theguiding structure are particularly useful with cages of a round orcylindrical configuration, as described below, though they may also beused in any of the embodiments of the present disclosure disclosedherein.

The shim may be configured to be used with any number of cageconfigurations, shapes and sizes. For example, and without wishing to belimited to any one embodiment, the shim may be of a generallyrectangular or square configuration and thus operable with therectangular or square embodiments of the cage of the present disclosuredescribed above. Additionally, the shim may be shaped in a cylindrical,tubular, conical, circular, arced or rounded manner so as to be operablewith the cylindrical or rounded embodiments of the cage of the presentdisclosure described below. For purposes of the present disclosure, theshim may be of any shape and/or size desired including, withoutlimitation, square, rectangular, triangular, round, circular, tubular,cylindrical, polygonal, conical, and any other shape that may be of usewith an implantable intervertebral fusion cage of the presentdisclosure. It is yet another embodiment of the present disclosure thatthe shim comprise multiple sides or multiple members—for example, theshim may have a top member and at least one side member, wherein the atleast one side member is operable to contact or otherwise reversiblyengage the openings or fenestrations of the cage and serve tosubstantially block fluid communication between the hollow interior andthe exterior of the cage. In yet another embodiment, the shim may becomprised of a plurality of members that are interconnected by aconnecting member including, for example, a wire, a cable and anothermember. One having ordinary skill in the art will appreciate that a shimthat is configured to lie in more than one plane (i.e., have more thanone member or have a curvature) may additionally be configured toreversibly self-adhere, attach, engage, slide, assemble or clamp ontothe cage of the present disclosure. This self-adhering or clampingaspect may be achieved by mechanical means (e.g., by frictional force,compressive force), electrical means (e.g., piezoelectric device), ormagnetic force. This self-adhering or clamping aspect may obviate theneed for a ridge on the fusion cage. See FIG. 7C. In accordance withaspects of the present invention, one having ordinary skill in the artwill appreciate that a shim that is configured to lie in more than oneplane may be configured with members that operably engage more than oneside a fusion cage, and thereby substantially block fluid communicationbetween the hollow interior and the exterior of more than one side ofthe fusion cage. A shim that is configured to lie in more than one planeand reversibly self-adhere or clamp to a fusion cage may also beconfigured to be selectively released from the fusion cage by, forexample, a mechanical force (e.g., a stress or strain force), magneticforce or electrical means. In accordance with other aspects of thepresent disclosure, the selective release or removal of the shim fromthe fusion cage will restore fluid communication between the hollowinterior and the exterior of the fusion cage.

In certain embodiments, more than one side or portion of a cage iscontacted by one or more shims. For example, without intending to belimiting, FIG. 6 shows an embodiment of a cage (e.g., round) where twoshims are employed to cover desired surfaces of the cage, thuspreventing liquid from escaping the cage. As otherwise described herein,the shims employed may be of any suitable geometry or combination. Forexample, a single circular shim could be used; one or more shims couldbe used in combination to achieve the desired preclusion of leakage offluid from within a cage structure. Both insertion as well as removal ofmore than one shim, substantially simultaneously, may be achieved, thusreducing the number of operations required to provide a loaded cagestructure. The end portions of one or more shims could be configured torender easy manipulations of the one or more shims by a tool.

With specific reference now to FIGS. 5A, 8A and 8B, the shim 404, 804preferably includes a projection or tab 508, 808 located at one end thatprojects beyond the outer perimeter of the cage and which serves tofacilitate removal of the shim 404, 804. This projection or tab may varyin size to accommodate numerous surgical processes and its width mayvary from relatively thin to the width 816 of the shim itself and itslength may vary from relatively short to quite long. For example, andwithout wishing to be limited to any one embodiment, a user may graspthe projection or tab at the desired time of removal and pull it inorder to remove the shim 804 from being in contact with the guidingstructure(s). Alternatively, the projection or tab 808 may be configuredto attach to a surgical tool such that the surgical tool may be used asthe means of removing the shim. Optionally, the shim may also include anopening or hole through which a line or thread may be tied, or asurgical instrument may be inserted, in order to facilitate removal ofthe shim 804 from the cage. With specific reference now to FIGS. 8A and8B, a shim is shown with a tab in one embodiment of the presentdisclosure. FIG. 8A shows a top aspect view of the shim 804 with theassociated tab 808. One having skill in the art will appreciate that thetab may be of a material and dimensions (thickness, width, and length)different than that of the shim. The shim is shown to have a width 816and a length 812. FIG. 8B shows a side aspect view of the shim 804 withthe associated tab 808. The shim is shown to have a thickness 820. Inone embodiment of the present disclosure, the thickness 820 of the shimis preferably between 0.4 mm and 0.75 mm inclusive. In some embodiments,this opening or hole is present in the projection or tab 808.

The guiding structure of the present disclosure may be present along theexternal surface in any number of manners. For example, in someembodiments the guiding structure is cast or machined with the cage asan extension of the external surface of the cage itself, thereby makingthe guiding structure a physical, continuous extension of the cage body.In other embodiments, the guiding structure is ground out of theexterior surface of the cage wall. In these embodiments, the guidingstructure may be ground out at the time the cage is ground out of aportion of a larger material, or the guiding structure may be ground outin advance of implantation in order to provide a customized guidingstructure. In still other embodiments, the guiding structure may be aseparate piece that is attached to, or secured onto, the externalsurface of the cage prior to implantation. The guiding structure ofthese embodiments may be secured onto the external surface any one ormore of many standard means by which two structures may be operablyconnected together, such as with the use of adhesives, welding, bands,straps, threading, a clamp, a snap-fit assembly, a bolted or screwedconnection, a push-on/turn-on self-locking fastener, a press fit,rivets, and/or other, similar means. In other embodiments of the presentdisclosure, the ridge may be present on the internal surface of thecage.

In accordance with at least some aspects of at least one embodiment ofthe present disclosure, a surgically implantable intervertebral fusioncage is provided, the cage having a hollow frame that is substantiallytubular, cylindrical or conical in shape. For purposes of illustration,and without wishing to be held to any one embodiment, the following U.S.patents and U.S. patent Publications are incorporated herein by thisreference in order to provide an illustrative and enabling disclosureand general description of an intervertebral fusion cage that issubstantially tubular, cylindrical or conical in shape: U.S. Pat. No.5,653,763 to Errico et al.; U.S. Pat. No. 5,665,122 to Kambin; U.S. Pat.No. 5,888,228 to Knothe et al.; U.S. Pat. No. 6,648,915 to Sazy; U.S.Patent Application Publication No. 2004/0143330 to Sazy; U.S. PatentApplication Publication No. 2005/0149192 to Zucherman et al.; and U.S.Patent Application Publication No. 2005/0149193 to Zucherman et al. Eachof the foregoing known cages have the same basic tubular, cylindrical orconical construction and, for the sake of simplicity, will be referredto herein as having a main wall that is tubular, cylindrical, or conicalin shape and/or configuration, a first end wall and a second end wall,each end wall being interconnected with the main wall so as to form aclosed tube, cylinder, or cone in that the main wall is connected to thefirst end wall and to the second end wall in such a way that the mainwall, first end wall and second end wall, when fully interconnected,define a hollow interior to the cage that is tubular, cylindrical orconical in shape and/or configuration. In some embodiments, theintervertebral fusion cage of the present embodiment has a diameterranging from about 8 mm to about 18 mm and a length ranging from about18 mm to about 55 mm. Thus, both the first and wall and the second endwall preferably have a diameter that ranges from about 8 mm to about 18mm and the main wall has a length that ranges from about 18 mm to about40 mm. When fully constructed, the tubular, cylindrical or conicalshaped cages have an elongated appearance such that they are longer thanthey are tall, making the largest points of contact of the cage with thetarget vertebrae two arcs along the external surface of the main wall,one at the top of the surgical site that makes contact with one of thetarget vertebrae and one at the bottom of the surgical site that makescontact with a second target vertebra. The first end wall and the secondend wall may also make contact with the target vertebrae, though it ispreferable that the major points of contact with the target vertebraewill occur via the exterior surface of the main wall.

The main wall has at least one opening or fenestration, and preferably aplurality of openings or fenestrations, located along its length thatprovide a location, or locations, where material that is placed orstored inside of the hollow interior may freely move from the hollowinterior to the exterior of the cage. The at least one opening orfenestration thus allows for fluid communication between the hollowinterior 620 of the cage and the outside of the cage in a similar manneras described above. See, e.g., FIG. 6.

Additionally, the exterior surface of the main wall has at least oneguiding structure located on it, which is configured to hold a shield orshim in place along the exterior surface of the main wall. In someembodiments, a single, T-shaped guiding structure runs the entire lengthof the exterior surface such that a single shield or shim can be wrappedaround the full exterior circumference of the main wall and be held inplace by making contact with both sides of the T-shaped guidingstructure. As stated above, all embodiments of the guiding structure maybe used to secure one or more shims to the external surface of a cage ofthese embodiments, though the embodiment of the guiding structure thatis particularly useful for a cage of this shape and/or configuration ispreferably the T-shaped guiding structure shown and described above. Inother embodiments and with specific reference now to FIG. 6, theexternal surface has at least one guiding structure, and may also have aplurality of guiding structures, located on it and there may be twoguiding structures 608 running the length of two opposing sides of theexternal surface such that two shims, a first shim 612 and a second shim616, are held in place along two opposing sides of the external surface604. In one embodiment, there are a plurality of guiding structuresholding the shim in place, at least one running the length of theexternal surface as previously described and at least one located in abelt-like fashion around the entire perimeter of the external surfacesuch that the shim slides under the at least one belt-like guidingstructure, makes contact with the other at least one guiding structure,and is held in place accordingly. One having ordinary skill in the artwill appreciate that in one embodiment where the fusion cage has only asingle guiding structure running the length or part of the externalsurface, an arcuate shim may be configured whereby at least one edge ofthe shim makes contact with the guiding structure. In yet anotherembodiment and as described above, the fusion cage may not have anyguiding structure on its external surface, and a shim may be configuredto engage the fusion cage in a complementary fashion.

As mentioned above, the main wall has at least one, and preferably aplurality of, openings or fenestrations through it that allow for themovement of material out of the hollow interior and toward the targetvertebrae. Therefore, when a shim is held in place by a guidingstructure along the exterior surface of the main wall, the shim at leastpartially blocks or covers, and preferably completely blocks or covers,the at least one opening or fenestration located along and through themain wall. When the at least one opening or fenestration, and preferablythe plurality of openings or fenestrations, are covered or blocked inthis manner, the shim serves to prevent the movement of material aspreviously described. Additionally, when the shim is removed fromcontact with the guiding structure(s) located along the external surfaceof the main wall, fluid communication is restored as previouslydescribed.

The surgically implantable intervertebral fusion cages of the presentdisclosure, inclusive of the guiding structures of the presentdisclosure, may be made of any kind of material suitable for surgicalimplantation that is also sufficiently rigid so as to provide therequired support between the target vertebrae, such as steel or medicalgrade plastic. In some embodiments, the guiding structure is an integralpart of the cage and the two structures are cast or machined as asingle, continuous unit. The cages and the guiding structures may bemade of: surgical stainless steel of the general alloy type of iron,carbon, chromium (12-20%), molybdenum (0.2-3%), and nickel (8-12%);martensitic steel; 316L or 316LVM austenitic steel; and/or 316 surgicalsteel. It is desirable for the cages and guiding structures of thepresent disclosure to be quite rigid and strong in construction so as toprevent any deforming during use and/or after surgical implantation,which can cause a loss of function.

Referring now to FIGS. 7A and 7B, several of the embodiments of thefusion cage of the present disclosure include a securing site 712 thatis configured to be contacted with at least a portion of an impactor orholder, a width 720, a length 724, a least one opening or fenestration708, and at least one ridge 704. In these embodiments, the securing site712 is configured so that the impactor or holder secures the fusion cageto a distal end portion of the impactor or holder and keeps the fusioncage so secured until such time as the user desires to remove theimpactor or holder from the securing site 712 of the fusion cage.Therefore, the securing site 712 is configured so that the fusion cagecan be releasably secured to the distal end portion of the impactor orholder. In some embodiments, the securing site 712 is a cavity orindentation located in an exterior portion of a single wall of thefusion cage that does not proceed through the entirety of the wall andthus does not provide a location where material may move from theinterior of the fusion cage to the exterior of the cage. The securingsite 712 may be located in any wall of the fusion cage of the presentdisclosure, though it is preferable for the securing site to be locatedin a lateral wall or an end wall of the fusion cage so as not tointerfere with the openings or fenestrations 708 of the cage and tofacilitate surgical implantation of the cage. It is also preferable forthe securing site to be configured to be complimentary in size and shapeto the distal tip 1618, 1818 of an internal member of the impactor orholder, to facilitate securing of the fusion cage to the distal end1616, 1816 portion of the impactor or holder. The securing site 712 maybe of any shape and configuration that is typically used to securelyhold two objects together. By way of example, and without wishing to belimited to any one embodiment, the shape and configuration of thesecuring site may be any one or more of many standard shapes andconfigurations typically used to operably connect two structurestogether, such as threading, a clamp, a snap-fit assembly, a bolted orscrewed connection, a push-on/turn-on self-locking fastener, a press fitand/or other, similar shapes and configurations. In some embodiments,the securing site 712 is threaded. The use of the securing site 712, inconjunction with the distal tip 1618 of the internal member of theimpactor or holder, is described below. Referring specifically now toFIG. 7C, a side view of a cage is shown without a ridge 704. Asdescribed above, this fusion cage may be suitable for use with a shimthat is self-adhering or attaching to the fusion cage.

The shims of the present disclosure may be made of any kind of materialsuitable for surgical implantation that is rigid enough to completelyprevent the movement of viscous materials from the hollow interior whenthe shim is in place along the exterior surface, but that is alsosufficiently flexible so as to be readily removable and replaceablewithout being damaged or undergoing substantial plastic deformation.Suitable materials include, for example, plastic,poly(tetrafluoroethene) or poly(tetrafluoroethylene), or plastastic,though the shims may also be made of polyamide, polyethylene,polypropylene, polyphenylene sulfide, polyurethane,poly(tetrafluoroethylene), polyvinyl chloride, or polyvinylidenefluoride. In some embodiments, the shim includes at least one portionthat is radiopaque, or that prevents the penetration of x-rays orsimilar forms of radiation. In some embodiments, the shim includes atleast one portion that is a radio transmitter. In a more preferableembodiment, each shim has a plurality of radio transmitters 1112 thatmay be used in concert by a radio receiving device to determine theorientation and position of the shim, and therefore the fusion cage towhich the shim is attached. See, FIG. 10A. In some embodiments each shimhas a plurality of radiopaque portions 1112. See, FIG. 10A. Theseembodiments may be useful in conjunction with x-rays in order todetermine whether the fusion cage of the present disclosure, having atleast one such shim in place along an external surface, is being or hasbeen properly oriented and/or inserted into the surgical site. Theradiopaque portion may be an integral part of the shim itself, or may bean additional component that is put into contact with a portion of theshim. Any suitable radiopaque material may be used for the shims ofthese embodiments, including, without limitation, radiopaquethermoplastic compounds, such as LATIGRAY by LATI IndustriaTermoplastici S.p.A., lead, ceramic, radiopaque polyolefin compounds,poly(methyl methacrylate), transition metals such as those present inGroups IIIB through IIB of the Periodic Table of the Elements, salts ofsuch transition metals, nontransition metals such as those found inPeriods 3 through 7 of Groups IA and IIA of the Periodic Table of theElements, and salts of such nontransition metals. In some embodiments,the shims may be made of an absorbable or resorbable biologic materialor may be made of a permeable mesh. Furthermore, the shims may bebelt-like and recessed beneath a PEEK isthmus. The shims may also besemi-metallic so that they are radio-opaque and may, in and ofthemselves, be made of a material that incorporates in the fusion as abone or fusion stimulant.

The size and shape of the projection or tab may vary between embodimentsof the shim and the scope of the present disclosure is intended toinclude a projection or tab of any shape and/or size. In someembodiments, the projection or tab extends a short distance beyond theexternal face of the fusion cage when the shim is in place and isgenerally of a rectangular, square or polygonal shape. See, e.g., FIGS.4 and 5A. In these embodiments, the projection or tab may be used toremove the shim from contact with the at least one guiding structure,and therefore from contact with the external surface of the fusion cage,by grasping the projection or tab and pulling the shim away from thefusion cage. Alternatively, the projection or tab of these embodimentsmay include a hole through it so that a surgical instrument may beinserted into the hole and used to remove the shim, or so that surgicalthread or similar material may be placed through the hole, properlysecured and then used to remove the shim.

In other embodiments, the projection or tab is long and thin, extendingbeyond the external face of the fusion cage a greater distance when theshim is in place, and is generally of a rectangular or rounded shape.See, e.g., FIGS. 10A and 10B. In these embodiments, the projection ortab 1108 may be of sufficient length 1116 to remain outside of thepatient after proper insertion of the fusion cage into the patient,thereby allowing the user to grasp the projection or tab 1108 afterinsertion of the fusion cage and pull on it, removing the shim 804 fromthe cage. Alternatively, the projection or tab 1108 of these embodimentsmay also include features, such as guiding structures 1104 or crests, atthe distal end of the projection or tab that are used to secure thedistal end of the projection or tab to a clamp or similar structurelocated along the handle of a surgical instrument such as an impactor orholder. See, e.g., FIG. 10A. By securing the distal end of theprojection or tab to a surgical instrument, the user may pull on andremove the shim 804 from the external surface of the fusion cage bymerely removing the surgical instrument from the surgical site. The shim804 will be removed simultaneously with the surgical instrument. Theprojection or tab 1108 of these embodiments is preferably approximately4 cm to approximately 10 cm in length 1116, more preferablyapproximately 6 cm to approximately 9 cm in length, and is even morepreferably approximately 8 cm in length. See, e.g., FIG. 10B.

In accordance with at least some aspects of at least one embodiment ofthe present disclosure, a distraction wedge is provided, the distractionwedge having an elongated handle that is substantially cylindrical inshape and a head at a proximal end of the distraction wedge that isconfigured to generate an opening in tissue that is of the size andshape of the head portion of the distraction wedge, the head portionbeing offset from the handle portion by an angle such that the head andthe handle are not located in the same plane. See, e.g., FIG. 11A.Referring specifically to FIGS. 11A and 12, the distraction spacer isconfigured at an angle 1208, 1404 so that it may enter the disk spacewhen the operating cannula is not at a right angle to the disk space.For purposes of illustration, and without wishing to be held to any oneembodiment, the following U.S. patents are incorporated herein by thisreference in order to provide an illustrative and enabling disclosureand general description of a distraction wedge without a head portionbeing offset from the handle portion by an angle: U.S. Pat. No.5,836,948 to Zucherman et al.; U.S. Pat. No. 5,860,977 to Zucherman etal.; U.S. Pat. No. 5,944,658 to Koros et al.; U.S. Pat. No. 6,238,397 toZucherman et al.; U.S. Pat. No. 6,224,599 to Baynham et al.; U.S. Pat.No. 6,261,296 to Aebi et al.; and U.S. Design Pat. No. D374,283 toMichelson. Each of the foregoing discloses a distractor or distractionwedge having a head portion that is in the same plane as the handleportion and, for the sake of simplicity, will be collectively referredto herein as having a head portion and a handle portion. None of thecited references teaches or discloses the head portion being offset fromthe handle portion by an angle.

The handle of the distraction wedge is generally cylindrical in shapeand has a length ranging from about 140 cm to about 170 cm, andpreferably from about 160 cm to about 165 cm, and has a diameter rangingfrom about 4 mm to about 5 mm. The distal end of the handle mayoptionally include features for attachment to other surgicalinstruments, though this is not necessary for purposes of the presentinvention. The proximal, or head, end of the distraction wedge comprisesa head portion having a length ranging from about 15 mm to about 50 mm,a width ranging from about 40 mm to about 55 mm, and a height orthickness ranging from about 6 mm to about 16 mm. Thus, in someembodiments, the head portion is generally rectangular in shape. Thehead portion includes a proximal tip located at the proximal terminus ofthe head portion. In some embodiments, the proximal tip is pointed suchthat the height or thickness of the head portion and/or the width of thehead portion is gradually reduced from the head portion to the proximaltip, culminating in a pointed edge. See, e.g., FIGS. 11A and 11B. Thepointed edge is the initial portion of the distraction wedge to makecontact with the target tissue, and thus facilitates dissection of thetarget tissue by displacing the tissue as it is moved forward into thetissue. The pointed tip thus makes it easier for the user to move thedistraction wedge into the target tissue. The head portion of thedistraction wedge is offset from the handle portion by an angle rangingfrom approximately 5 to 45 degrees, and preferably from about 15 to 25degrees. See, e.g., FIGS. 11A and 11B.

In some embodiments and referring now to FIG. 11A, the head portion ofthe distraction wedge includes at least one recess or window located ona width face of the head. The at least one recess or window is presentonly on a single side of the distraction wedge and does not pass throughthe entire head portion of the distraction wedge. The at least onerecess or window may be of any size or shape and the present disclosureis intended to include recesses and/or windows of any size and shapethat are capable of fitting on the head portion of the distractionwedge. In some embodiments, the at least one recess or window isgenerally square or rectangular in shape. The at least one recess orwindow may be used in conjunction with x-rays or similar forms ofradiation to view the distraction wedge during use to determine whetherit has been properly positioned in the surgical site.

The distraction wedges of the present disclosure may be made of any kindof material suitable for surgical use, such as aluminum, iron, titanium,steel, medical grade plastic, surgical stainless steel of the generalalloy type of iron, carbon, chromium (12-20%), molybdenum (0.2-3%), andnickel (8-12%); martensitic steel; 316L or 316LVM austenitic steel;and/or 316 surgical steel.

In accordance with at least some aspects of at least one embodiment ofthe present disclosure and referring now to FIG. 13A, an impactor orholder is provided, the impactor or holder having an elongated, hollowhandle 1610 that is substantially cylindrical in shape, a distal endportion having an annular projection or lip 1622, at least one clamp1612 located on the external surface of the handle portion at a distancefrom the distal end portion, and an internal member 1608 located insideof the hollow handle 1610 that comprises a distal end 1616, a shaft1614, and a proximal end 1604, and that is configured to rotate aboutits longitudinal axis upon prompting by the user, the distal end 1616portion being offset from the handle portion by an angle 1620 such thatthe distal end 1616 and the handle 1604 are not coaxial.

For purposes of illustration, and without wishing to be held to any oneembodiment, the following U.S. patents are incorporated herein by thisreference in order to provide an illustrative and enabling disclosureand general description of a hollow impactor or holder without a headportion being offset from the handle portion by an angle: U.S. Pat. No.6,004,326 to Castro et al.; and U.S. Pat. No. 7,004,946 to Parker et al.Both of the foregoing discloses an impactor or holder having a headportion that is in the same plane as the handle portion and, for thesake of simplicity, will be collectively referred to herein as having ahead portion and a handle portion. Neither reference teaches ordiscloses the head portion being offset from the handle portion by anangle.

Referring once again to FIG. 13A, the hollow handle 1610 of the impactoror holder is generally cylindrical in shape and has a length rangingfrom about 140 cm to about 170 cm, and preferably from about 160 cm toabout 165 cm, an outer diameter ranging from about 5 mm to about 6 mm,and an inner diameter ranging from about 2 mm to about 3 mm. The distalend 1616 portion has an annular projection or lip 1622 that is alsooffset from the handle portion by an angle 1620. Referring now to FIG.13B, the annular projection or lip 1622 serves as a point of contact fora fusion cage 1624, such that when a fusion cage 1624 is being held inplace by the impactor or holder, it contacts the annular projection orlip 1622. FIG. 13B illustrates the impactor or holder assembled to thefusion cage 1624. In some embodiments, when a fusion cage 1624 is heldin place by the impactor or holder, the fusion cage is tightly contactedwith the entire distal face of the annular projection or lip 1622. Inthese embodiments, the annular projection or lip 1622 prevents thefusion cage 1624 from moving during placement into the patient. Onehaving ordinary skill will appreciate that in an alternate embodiment,instead of a fusion cage 1624, a pointed distraction tool as illustratedin FIGS. 11A and 11B may be assembled to the distal end 1616 of theimpactor or holder. One having ordinary skill in the art will alsoappreciate that the annular lip 1622 may have features on the side thatengages with the fusion cage 1624 to have a stabilizing effect tostabilize the fusion cage 1624 and prevent unwanted rotation or movementof the fusion cage 1624 during its assembly to the distal end 1616 andduring its release from the distal end 1616. Such a feature may include,for example, a tab, a pin, a ridge, a dowel or an indexing pin. It willbe appreciated that the fusion cage 1624 will have a corresponding, andcomplementary feature that engages or is engaged by the feature on theannular lip 1622 including, for example, an aperture, an indexing notch,a registration tab or notch, a slot or a groove.

In some embodiments, the impactor or holder includes an internal member1608 that is configured to rotate about its longitudinal axis whenprompted by the user of the impactor or holder. In these embodiments,the internal member is also configured to releasably secure embodimentsof the spinal fusion cage to a distal end 1616 portion of the impactoror holder and to keep the fusion cage 1624 secured to the distal endportion during surgical implantation of the spinal fusion cage 1624, andto release the fusion cage 1624 once it is in place at the desiredsurgical site when prompted by the user. The internal member 1608 may bea wire, rod or cable that is sized to fit within the inner diameter ofthe hollow handle 1610 of the impactor or holder and to rotate freelytherein, without interference from the inner walls of the impactor orholder. The internal member 1608 may have, at its proximal end 1604, ameans by which the user may releasably secure the spinal fusion cage tothe distal end 1616 of the impactor or holder. In some embodiments, thismeans is a thumbwheel or thumbscrew 1606 that is secured to the distalend 1616 of the internal member such that, when the thumb screw 1606 isrotated by the user, the internal member 1608 rotates about itslongitudinal axis. In these embodiments, it is preferable for the thumbscrew 1606 to be configured so that it may rotate in both directions. Asshown in the figure, it is yet another aspect of the present disclosurethat a shield 1602 may be configured to encompass the thumb screw 1604while at the same time providing operational access to the thumb screw1604. The shield 1602 may be a stiff band or projection that is attachedto the handle 1610 and projects above the thumb screw 1606. The shield1602 provides a location whereby the user of the impactor or holder mayapply a force such as by thumping, percussing or striking the shield1602 of the impactor or holder using, for example, a hammer or otherfirm device. One having ordinary skill in the art will appreciate thatthe force imparted to the shield 1602 is transmitted to the handle 1610,and in turn transmitted through the projection or lip 1622 to the adevice secured on the distal end 1616 of the impactor or holder tool.Also in these embodiments, the distal tip 1618 of the internal member isconfigured to be complimentary in size and shape to the securing site712 of the spinal fusion cage, to facilitate securing of the fusion cageto the distal end 1616 portion of the impactor or holder. The distal tipof the internal member is thus configured so that, when the thumb screwis rotated in a first direction, the distal tip 1618 of the internalmember is tightened into the securing site 712, thus securing the fusioncage in contact with the annular lip 1622 of the impactor or holder.Similarly, the distal tip 1618 of the internal member is thus configuredso that, when the thumb screw 1606 is rotated in a second direction, thedistal tip 1618 of the internal member is released from the securingsite, thus releasing the fusion cage from contact with the annular lipof the impactor or holder. In these embodiments, it is preferable forthe distal tip 1618 of the internal member to be threaded so that whenthe internal member 1608 is rotated in the first direction by the meansfor rotating, the distal tip 1618 is moved into the securing site (whichis preferably threaded in a complimentary manner) and so that when theinternal member 1608 is rotated in the second direction, the distal tip1618 is moved out of the securing site. Preferably, when the distal tipis moved into the securing site, the threading serves to secure thefusion cage to the annular lip 1622 of the impactor or holder. It istherefore useful for the user to move the distal tip 1618 of theinternal member 1608 into the securing site by an amount that will besufficient to engage enough threading to hold the fusion cage to theimpactor or holder via the securing site.

In alternate embodiments, the internal member may be configured as aspring that is configured to move in a longitudinal direction within thelength of the impactor or holder. In these embodiments, the means bywhich the user may releasably secure the spinal fusion cage to thedistal end of the impactor or holder may be a plunger, configured to bepressed by the user. Similarly, the distal tip of the internal membermay be configured so that it serves to hold the fusion cage to theannular lip of the impactor or holder via means that can be secured by aspring, or plunger, type motion. These means for securing may include,without limitation, a clamp, a snap-fit assembly, a push-on/turn-onself-locking fastener, and/or a press fit assembly.

In some embodiments, the impactor or holder includes at least onestructure 1612 located along its outer diameter at some distance fromthe annular lip or projection that is configured to engage and secure aportion of a projection or tab of a shim. In these embodiments, thestructure 1612 can be configured such that it secures a terminal end ofan extended projection or tab 508, 808 of a shim, which has been securedagainst an external face of a fusion cage, and holds that terminal endof the shim in place along the external length of at least a portion ofthe impactor or holder while the fusion cage is in contact with theannular lip of the impactor or holder. See, e.g., FIG. 13B. In someembodiments, a plurality of such structures is present on the impactoror holder. Preferably, the number of these structures will equal thenumber of shims in use with the fusion cage. In use, these structurescan serve to remove the shim from the fusion cage simultaneously withthe removal of the impactor or holder from the surgical site, as theterminal ends of the shim(s) will be secured in place at the structuresso that, when the fusion cage has been delivered and the impactor orholder is removed from the surgical site, the terminal end of the shimswill remain held in place along the external length of at least aportion of the impacter or holder. The motion of removing the fusioncage from the surgical site thus also serves to remove the shims fromcontact with the external surface of the fusion cage. In someembodiments, these structures are C-clamp like structures that arecapable of securely holding the terminal end of a projection or tabduring surgical implantation of the fusion cage. See, e.g., FIGS. 13Aand 13B.

The impactor or holder of the present disclosure may be made of any kindof material suitable for surgical use, such as aluminum, iron, titanium,steel, medical grade plastic, surgical stainless steel of the generalalloy type of iron, carbon, chromium (12-20%), molybdenum (0.2-3%), andnickel (8-12%); martensitic steel; 316L or 316LVM austenitic steel;and/or 316 surgical steel. The internal member of the impactor or holderof the present disclosure may be a wire, rod or cable, each of which maybe made of any kind of material suitable for surgical use, such asaluminum, iron, titanium, steel, medical grade plastic, surgicalstainless steel of the general alloy type of iron, carbon, chromium(12-20%), molybdenum (0.2-3%), and nickel (8-12%); martensitic steel;316L or 316LVM austenitic steel; and/or 316 surgical steel. Thestructure(s) configured to engage and secure a portion of a projectionor tab of a shim may be made of the same materials as listed above, andmay also be made of medical grade plastic.

In accordance with at least some aspects of at least one embodiment ofthe present disclosure, a method of surgically implanting anintervertebral fusion cage into a patient is provided. The methodcomprises obtaining a surgically implantable intervertebral fusion cagehaving at least one wall, at least one guiding structure located on anexterior surface of the at least one wall, and at least one removableshield or shim. The at least one wall defines a hollow interior to thecage and has at least one opening or fenestration in it that allows forfluid communication between the hollow interior and an exterior of thecage. The guiding structure is operable to hold the at least one shim incontact with the exterior surface and is configured to allow the atleast one shim to be freely removed from, and replaced onto, theexterior surface of the wall.

The method further includes preparing the cage for surgical implantationby filling the hollow interior with a material capable of fusing twobony structures, preferably two vertebrae, and more preferably twoadjacent vertebrae, together and contacting the at least one shim withthe exterior surface of the cage by positioning the shim under at leasta portion of the at least one guiding structure such that the at leastone shim is contacted with and held in place along the exterior surfaceby the at least one guiding structure by way of such contact. In someembodiments, when the at least one shim is contacted with the at leastone guiding structure, the shim at least partially covers or blocks theat least one opening or fenestration, preventing fluid communicationbetween the hollow interior and the exterior of the cage, and preventingthe material from leaving the hollow interior.

After the cage has been prepared for implantation, the method includeslocating an appropriate surgical site in a patient for implantation ofthe cage. The surgical site may be an intervertebral location, includingthe space typically filled by an intervertebral disc, but may also beany location in a patient where two bony structures are to be fusedtogether. A surgical opening is created in the patient that willaccommodate the cage. This opening may be made dorsally, ventrally,laterally or at any other location along the patient that is medicallyefficacious to grant the user access to the surgical site. The cage isthen surgically implanted into the patient and positioned in thesurgical site between the desired bony structures, and preferablybetween the two adjacent vertebrae of interest, in such a way that willserve to utilize the material in connection with the patient's ownsystems to promote the fusion of the two bony structures by way of, andthrough, the cage. Thereafter, the at least one shim is removed fromcontact with the guiding structure and the exterior surface of the cage,thereby restoring fluid communication between the hollow interior andthe exterior of the cage and allowing the material to move from thehollow interior to the exterior of the cage. Once these tasks arecompleted, the method is concluded by closing the surgical opening inthe patient.

In accordance with still other aspects of the present disclosure, afurther method of surgically implanting an intervertebral fusion cageinto a desired location within a patient is provided. In at least oneembodiment of these aspects of the present disclosure, the methodincludes obtaining a cage having: (i) at least one wall defining ahollow interior of the cage, the wall having at least one opening orfenestration in it that allows for fluid communication between thehollow interior and the exterior of the cage; (ii) at least oneconstraining structure, such as a guiding structure, on an exteriorsurface of the wall that is configured to reversibly hold at least oneshim in place along the exterior surface of the wall, wherein the atleast one guiding structure is configured to allow the at least one shimto be removed from, and replaced onto, the exterior surface of the wall;(iii) at least one removable shim; and (iv) means for receiving asecuring element capable of securing the cage to a distal end portion ofan impactor or holder. The method further includes preparing the cagefor surgical implantation by filling the hollow interior with a materialthat is capable of fusing two vertebrae, or other bony structures,together and placing the at least one shim in contact with the exteriorsurface of the cage such that the at least one shim is secured or heldin place along the exterior surface by the at least one guidingstructure and wherein the at least one shim substantially blocks the atleast one opening or fenestration, thereby substantially preventingfluid communication between the hollow interior and the exterior of thecage and thereby retaining at least most of the material inside of thehollow interior. The method further includes locating an appropriatesite inside of the patient for implantation of the cage, positioning thepatient (e.g., laterally, posteriorly or anteriorly) so as to obtain thedesired amount of exposure of the desired surgical site, and creating asurgical opening in the patient that exposes the desired surgical siteand that is sufficient to accommodate the cage. The surgical site may bean intervertebral location, including the space typically filled by anintervertebral disc, but may also be any location in a patient where twobony structures are to be fused together.

Once the opening is created, the method further includes generating asufficient amount of distraction, or an opening of desired size andshape, at the surgical site by inserting a distraction wedge into thepatient, contacting the distraction wedge with the tissue to be opened,and moving the distraction wedge into the tissue to be opened until thedesired shape and depth of distraction, or opening, is created in thetissue to be opened. Thereafter, the method further includes surgicallyimplanting the cage into the patient in such a way that the fusion ofthe two vertebrae or other bony structures will occur upon exposure tothe material, by securing the cage to a distal end portion of animpactor or holder, moving the cage and impactor or holder into thesurgical opening, contacting the cage with the site of surgicalimplantation, and moving the cage into the surgical site. Thereafter,the cage is selectively released from the distal end portion of theimpactor or holder and the impactor is removed from the surgicalopening. The method is concluded by closing the opening in the patient.

In some embodiments of this method, during the preparation of the fusioncage for implantation, the projection or tab of the at least one shim isplaced in contact with a structure located along the outer diameter ofthe impactor or holder and secured along the outer diameter by thestructure. In these embodiments, the method further includes removingthe at least one shim from contact with the guiding structure, and thusthe exterior surface of the wall, simultaneously with the removal of theimpactor or holder from the surgical opening, thereby restoring fluidcommunication between the hollow interior and the exterior of the cageand allowing the material to move from the hollow interior to theexterior of the cage. In other embodiments of this method, the at leastone shim is removed after the impactor is removed from the surgicalopening via a pulling force exerted on the projection or tab of the atleast one shim.

In some embodiments, the step of positioning the patient includeslaterally positioning the patient, or placing the patient on his or herside, so that the portion of the intervertebral space into which afusion cage is to be implanted is closer in proximity to the health careprovider than if the patient were to be placed on his or her other side.In these embodiments, the step of positioning further includes maximallybending the patient laterally so that the side that is closer inproximity to the health care provider is maximally arched, with thepatient's other side being minimally arched, rendering the surgical siteof interest in as open a configuration as possible. In furtherembodiments, the patient is maximally bent laterally so as to maximizethe distance between the patient's lower-most rib and the patient'siliac crest.

In some embodiments of the present disclosure and referring specificallynow to FIGS. 14A and 14B, a distraction wedge and/or an impactor orholder having a handle 1810 and a distally-located rotating hinge 1832is provided, wherein the handle 1804 has an input means 1806 forcommunicating with the distal end of the body. The input means 1806 maycomprise, for example, a trackball, a rotating member, a lever, anelectronically controlled signal, a button, or another structuralfeature that provides desired movement at the opposite end of the tool.In one embodiment, the input means 1806 is a thumbscrew that is incommunication with the shaft 1808, which may be a rotating memberincluding, for example, a cable, a shaft or other rotating means. Theshaft 1808 is in communication with the distal tip 1818, providingthereby, communication between the input means 1806 and the distal tip1818. The rotating hinge 1832 is configured to allow the head portion ofthe distraction wedge and/or the distal end 1816 portion of the impactoror holder to rotate in at least one plane about an axis and thereby beoffset from the handle 1810 of the distraction wedge and/or an impactoror holder, and from the external shaft 1836, by an angle, and whereinthe exterior shaft 1810 is configured to change the angle of therotating hinge 1832 and to lock the rotating hinge 1832 in place at adesired angle. The rotating hinge 1832 is also configured to providecommunication between the input means 1806 and the distal tip 1818. Onehaving skill in the art will appreciate the devices or methods that maybe used to provide the aforementioned communication. These methods mayinclude, for example, a cable, a universal joint, a constant velocityjoint.

One having ordinary skill in the art will appreciate that in certainembodiments, the rotating hinge 1832 may be one or more of anelectronically, hydraulically or pneumatically actuated device, wherebyone or more of the angle of rotation, the movement and the locking ofthe rotating hinge may be controlled electronically, hydraulically orpneumatically. If the rotating hinge 1832 is controlled by electronicmeans, the control may be performed by a remote user through anelectronic signal or radio signal. One having ordinary skill in the artwill further appreciate that in certain embodiments, the input means1806 may be in communication with the distal tip 1818 by remote orindirect means including an electronic signal, a radio signal. As such,the input means 1806 may accept a mechanical input (e.g., a twistingmotion) or an electronic signal to correspondingly engage or cause aneffect on the distal tip 1818.

In these embodiments, the distraction wedge and/or the impactor orholder are as previously described and have the added features of theexternal shaft 1836 and the rotating hinge 1832. In some embodiments,the external shaft 1836 is a tube located along and around the exteriorsurface of the handle 1810 of the distraction wedge and/or impactor orholder (see, e.g., FIGS. 14A and 14B). The external shaft 1836 issubstantially cylindrical in shape, hollow and, in some embodiments, hasa distal end portion configured to operatively engage at least a portionof the rotating hinge 1836 in such a way so as to lock the rotatinghinge 1832 in place at a desired angle. The external shaft 1836 mayoptionally include a means for grasping 1824 the external shaft 1836located on its proximal terminus, wherein the means for grasping 1824 isconfigured so that the user can readily grasp the exterior shaft 1836and move it either forward or backward along the longitudinal axis ofthe handle. In some embodiments, the means for grasping is an annularlip 1824 (see, e.g., FIGS. 14A and 14B). The external shaft has a lengthranging from about 100 cm to about 170 cm, an outer diameter rangingfrom about 4 mm to about 8 mm, and an inner diameter ranging from about2 mm to about 7 mm. The external shaft 1836 of the present disclosuremay be made of any kind of material suitable for surgical use, such asaluminum, iron, titanium, steel, medical grade plastic, surgicalstainless steel of the general alloy type of iron, carbon, chromium(12-20%), molybdenum (0.2-3%), and nickel (8-12%); martensitic steel;316L or 316LVM austenitic steel; and/or 316 surgical steel.

The rotating hinge 1832 is integrated into the handle portion 1810 ofthe distraction wedge and/or the impactor or holder, thus providing apoint of separation between the handle portion 1810 and the head portionof the distraction wedge and/or the distal end 1816 portion of theimpactor or holder. In some embodiments, the rotating hinge 1832operates in a manner substantially identical to a door hinge, whereinthe rotating hinge allows the head portion of the distraction wedgeand/or the distal end 1816 portion of the impactor or holder to rotatefreely in at least one plane and/or at least one direction, in aback-and-forth manner. In other embodiments, the rotating hinge 1832operates in a manner substantially identical to a wave platform shaker,wherein the head portion of the distraction wedge and/or the distal endportion 1816 of the impactor or holder are attached to the rotatinghinge 1832 at a single point and wherein the rotating hinge isconfigured to allow the head portion and/or the distal end 1816 portionto rotate freely in three dimensions.

The rotating hinge 1832 allows the head portion of the distraction wedgeand/or the distal end 1816 portion of the impactor or holder to beoffset from the handle 1810 and from the exterior shaft 1836 by an angleso that they may be utilized as described herein without the need forthe handle of the distraction wedge and/or an impactor or holder or forthe exterior shaft to be aligned with the surgical site at a rightangle. In some embodiments, the angle of the head portion of thedistraction wedge and/or the distal end 1816 portion of the impactor orholder is determined by securing or locking means located at the distalterminus of the external shaft, which are configured to lock therotating hinge in place, and thereby set a desired angle of use for thehead portion of the distraction wedge and/or the distal end 1816 portionof the impactor or holder (see, e.g., FIGS. 14A and 14B).

In some embodiments, the locking means comprises at least one lockingpin 1834, which may be an extension of the external shaft 1836 itself orwhich may be a separate component secured to the distal terminus of theexterior shaft (see, e.g., FIGS. 14A & 14B). In the embodiment depictedin FIGS. 14A & 14B, the locking means is a pair of locking pins 1834,located on opposing sides of the exterior shaft 1836. In otherembodiments, the locking means can include, for example, a singlelocking pin 1834, a series of interlocking teeth, threading, a clamp, asnap-fit assembly, a bolted or screwed connection, a push-on/turn-onself-locking fastener, a press fit, or other, similar means of lockingtwo objects together. One having ordinary skill in the art willappreciate the different methods and device that may be used to lock therotating hinge 1832. In operation, the distal terminus of the exteriorshaft 1832 is configured so that, when the exterior shaft 1832 is movedalong the longitudinal axis of the handle 1810, the locking means (e.g.,a locking pin 1834) becomes engaged, or disengaged, with the rotatinghinge 1832. When the locking means is engaged with the rotating hinge1832, the head portion of the distraction wedge and/or the distal end1816 portion of the impactor or holder is secured in place and preventedfrom motion. Conversely, when the locking means is disengaged from therotating hinge 1832, the head portion of the distraction wedge and/orthe distal end 1816 portion of the impactor or holder is free to move toa desired angle. The exterior shaft 1810 is therefore configured so thatit can repeatedly retract the locking means from the rotating hinge andreengage the locking means with the rotating hinge and can thusrepeatedly secure the head portion of the distraction wedge and/or thedistal end 1816 portion of the impactor or holder in place in any meansdesired including, without limitation, in plane with the external shaftor out of plane by any desired angle. The rotating hinge 1832 is used tochange the angle of the head portion of the distraction wedge and/or thedistal end 1816 portion of the impactor or holder relative to the angleof the handle. The rotating hinge 1832 also has at least one receivingmeans that are capable of receiving the locking means and thus securingthe head portion of the distraction wedge and/or the distal end 1816portion of the impactor or holder in place at a desired angle. Thereceiving means may be a hole or recess that is capable of accommodatingthe locking means or may be of any configuration that will serve to lockthe head portion of the distraction wedge and/or the distal end 1816portion of the impactor or holder in place by the locking meansdescribed above.

In some embodiments, the rotating hinge 1832 is configured to rotate atleast backward and forward in at least one plane along an axis that issubstantially perpendicular to the longitudinal axis of the handle ofthe distraction wedge and/or the impactor or holder and that issubstantially perpendicular to the longitudinal axis of the exteriorshaft 1836. When the locking means is disengaged from the receivingmeans, the rotating hinge 1832 swings freely such that it may rotatefreely around this axis in at least one plane. Conversely, when thelocking means is engaged with the receiving means, the head portion ofthe distraction wedge and/or the distal end 1816 portion of the impactoror holder will be secured in place and no longer mobile such that therotating hinge will be locked at a desired angle relative to thelongitudinal axis of the handle. The rotating hinge 1832 is configuredso that it can freely rotate through all angles that are unimpeded bythe handle and may be secured or locked in place at any angle withinthis range. In some embodiments, the rotating hinge may have at leastone, and preferably a series, of preset angles; the presetting may beaccomplished by setting the receiving means at one or more desiredlocations 1840 along the axis of the rotating hinge 1832 so that thelocking means will only engage the rotating hinge 1832 at a desiredangle. By way of example, and without wishing to be limited to any oneembodiment, the rotating hinge may have present angles corresponding to−90 degrees, −60 degrees, −45 degrees, −30 degrees, 0 degrees, +30degrees, +45 degrees, +60 degrees or +90 degrees in a single plane ofmotion. However, the rotating hinge is capable of being locked by thelocking and receiving means at any desired angle, such as −90 degrees,−89 degrees, −88 degrees, −87 degrees, −86 degrees . . . and so on.

In some embodiments, the locking means may be engaged with the receivingmeans or disengaged from the receiving means during use. In theseembodiments, the exterior shaft may be utilized as described herein toengage and/or disengage the locking means from the receiving meansduring use so that the angle of the head portion of the distractionwedge and/or the distal end portion of the impactor or holder relativeto the longitudinal axis of the handle may be adjusted during a surgicalprocedure. In some embodiments, the exterior shaft includes at least onestructure 1812 located along its outer diameter (e.g., the handle 1810or external shaft 1836) at some distance from the distal terminus thatis configured to engage and selectively secure a portion of theprojection or tab 508, 808 of a shim 404, 804. In these embodiments, thestructure can be configured such that it secures a terminal end of theextended projection or tab 508, 808 of the shim that has been securedagainst the external face of a fusion cage of the present disclosure andholds the terminal end of the shim in place along the external length ofat least a portion of the outer diameter while the fusion cage issecured at the securing site. In some embodiments, a plurality of suchprojections or tabs 508, 808 is present on the outer diameter.Preferably, the number of these projections or tabs 508, 808 will equalthe number of shims in use with the fusion cage. These structures canserve to remove the shim from the fusion cage simultaneously with theremoval of the exterior shaft holder from the surgical site, as theterminal ends of the shim(s) will be secured in place at the structures1812 so that, when the fusion cage has been delivered and the exteriorshaft is removed from the surgical site, the terminal end of the shimswill remain held in place by the structures 1812. The motion of removingthe fusion cage from the surgical site thus also serves to remove theshims from contact with the external surface of the fusion cage. In someembodiments, these structures 1812 are C-clamp like structures that arecapable of securely holding the terminal end of a projection or tabduring surgical implantation of the fusion cage. In other embodiments,the shim is removed after the impactor or holder is removed from thesurgical opening.

In yet another embodiment, the shim may be removed before the impactoror holder is removed from the surgical opening. This may be effected bythe structures 1812 having, for example, retracting capability, aratcheting mechanism, or a spring-loaded mechanism. Information relevantto the current state of the art as it applies to the foregoing devicesor capabilities, including useful written, enabling descriptions of howto make and use various components, can be found in the following U.S.patents and U.S. patent Publications, the entire contents of which areincorporated herein by this reference: U.S. Pat. No. 7,478,577 toWheeler, U.S. Pat. No. 7,455,157 to Kimes et al., U.S. Pat. No.7,430,945 to Gauthier et al., U.S. Pat. No. 7,421,772 to Gao et al.,U.S. Pat. No. 7,413,065 to Guathier, U.S. Pat. No. 7,410,478 to Yang,U.S. Pat. No. 7,410,334 to McGrew, U.S. Pat. No. 7,399,041 to Prentneret al., U.S. Pat. No. 7,357,284 to Jauvin, and U.S. Pat. No. 7,316,070to Green.

Referring specifically now to FIG. 15, an impactor or holder is shownthat exemplifies a preferred use of embodiments of the presentdisclosure. The impactor or holder of FIGS. 14A and 14B has a device1504 secured at the distal end; the impactor or holder is angled at thehinge or rotating hinge 1832 or rotating member; and as described in theforegoing, the thumbscrew 1806 can communicate with the distal tip 1818of the impactor or holder to selectively engage or disengage the device1504. As illustrated and described in the foregoing, the annular lip1824 may be used to engage the external shaft 1836 and thereby lock orunlock the rotating hinge 1832 to set the handle of the impactor orholder at an angle 1508 relative to the device 1504.

FIGS. 16A and 16B illustrate an example of an intervertebral fusion cage9910 according to one broad aspect of the present invention. The fusioncage 9910 has a basic rectangular construction and, for the sake ofsimplicity, will be referred to herein as having a top wall 9912, abottom wall 9914 and four lateral walls 9916, which collectively formthe shape of a rectangle in that each lateral wall 9916 is connected toa single edge of the top wall 9912 at a top edge of the lateral wall9916 and the bottom edge of the lateral wall 9916 is connected to asingle edge of the bottom wall 9914 in such a way that the top wall9912, bottom wall 9914 and four lateral walls 9916, when fullyinterconnected, create a shape that is substantially rectangular orsquare-shaped and also define a hollow interior to the cage. In someembodiments, additional walls 9918 may be present, for example withinthe interior chamber of the cage in order to create at least twoseparate hollow interior chambers within the cage and the ridges andveneers 9924 of the present disclosure will operate identically withthese embodiments with no loss of function whatsoever.

The intervertebral fusion cage 9910 has a height H1 ranging from about 8mm to about 18 mm, a width W1 ranging from about 10 mm to about 12 mm,and a length L1 ranging from about 18 mm to about 40 mm. Thus, both thetop and bottom walls 9912, 9914 preferably have a length that rangesfrom about 18 mm to about 40 mm and a width ranging from about 10 mm toabout 12 mm, and each of the lateral walls 9916 have a length thatranges from about 18 mm to about 40 mm and a height ranging from about 8mm to about 18 mm. When fully constructed, the substantially rectangularor square shaped cages have a flat profile such that they are longer andwider than they are tall, making the largest points of contact of thecage with the target vertebrae the exterior surface of the top wall 9912and the exterior surface of the bottom wall 9914. The lateral walls 9916may also make contact with the target vertebrae, though it is preferablethat the major points of contact with the target vertebrae will occurvia the exterior surface of the top wall 9912 and the exterior surfaceof the bottom wall 9914.

Both the top wall 9912 and the bottom wall 9914 have at least oneopening or fenestration 9920, and preferably a plurality of openings orfenestrations 9920, that provide a location, or locations, wherefusion-promoting material that is placed or stored inside of the hollowinterior may freely move from the hollow interior to the exterior of thecage 9910. The at least one opening or fenestration 9920, thus allowsfor fluid communication between the hollow interior of the cage 9910 andthe outside of the cage 9910. The purpose of these openings orfenestrations 9920 is to provide a means by which a portion of amaterial (e.g. FPM or bone grafting material) that is placed inside ofthe hollow interior of the cage 9910 prior to implantation may escapefrom the hollow interior and make contact with the target vertebrae atthe top of the cage 9912 and at the bottom of the cage 9914, whileretaining a portion of the material inside of the hollow interior. Inthis way, the material makes contact with one of the target vertebrae atthe exterior surface of the top wall 9912 of the cage and makes contactwith another of the target vertebrae at the exterior surface of thebottom wall of the cage 9914, while at the same time there is sufficientmaterial remaining inside of the hollow interior so as to promote thefusion of the target vertebrae by the generation of bony or osseoustissue through and around the fusion cage 9910.

Additionally, at least one of the exterior surface of the top wall orthe exterior surface of the bottom wall has at least one ridge 9922located on it, which is configured to hold a shield or veneer 9924 inplace along the exterior surface of the particular wall. Preferably, theridge is present on at least two of the edges of the exterior surfacesuch that the shield or veneer 9924 is held in place by the ridge 9922along at least two, and in some embodiments, three sides of the exteriorsurface of the wall in question. As shown in FIGS. 16A and 16B, forexample, the external surface of the cage 9910 has a plurality of ridges9922 located on thereon and there are two ridges 9922 along two opposingedges of the external surface of the top wall 9912 such that the veneer9924 is held in place.

In some embodiments, as illustrated in FIGS. 16A and 16B, it ispreferable for at least one ridge 9922 to be located along the exteriorsurfaces of both the top wall 9912 and the bottom wall 9914 so that afirst veneer 9924 may be held in place by at least one ridge 9922 alongthe external surface of the top wall 9912 and a second veneer 9924 maybe held in place by at least one ridge 9922 along the external surfaceof the bottom wall 9914. As mentioned above, the top and bottom walls9912, 9914 have the at least one, and preferably a plurality of,openings or fenestrations 9920 through them that allow for the movementof material out of the hollow interior of the fusion cage 9910 andtoward the target vertebrae. Therefore, when a first veneer 9924 is heldin place by at least one ridge 9922 along the exterior surface of thetop wall 9912 and a second veneer 9924 is held in place by at least oneridge 9922 along the exterior surface of the bottom wall 9914, the firstveneer 9924 and the second veneer 9924 at least partially block orcover, and preferably completely block or cover, the at least oneopening or fenestration 9920 located along and through the top andbottom walls 9912, 9914. When the at least one opening or fenestration9920 is covered or blocked in this manner, the veneers 9924 serve toprevent the movement of material, such as FPM or bone grafting material,from the hollow interior to the exterior of the cage 9910. The veneers9924 thus serve to prevent or block the fluid communication that wouldotherwise exist between the hollow interior and the exterior of the cage9910. Therefore, when either the first and/or second veneer 9924 isremoved from contact with the ridges 9922 located along the externalsurfaces of the top wall 9912 and the bottom wall 9914, fluidcommunication is restored between the hollow interior and the exteriorof the cage 9910 and the material may move from the hollow interiorthrough the at least one opening or fenestration 9920 to the outside ofthe cage 9910.

It is also preferable for the at least one ridge 9922 to be configuredto hold or retain the veneer(s) 9924 in place along the external surfacein question sufficiently tightly so as to prevent the movement ofmaterial from the hollow interior to the outside of the cage 9910. It isthus another aspect of the present disclosure for the at least one ridge9922 to hold the veneer(s) 9924 in place along, and in direct contactwith, the external surface of the top and/or bottom wall 9912, 9914 sothat the veneer(s) 9924 lies flat, without any wrinkles or gaps, andsuch that the veneer(s) 9924 is held in contact with the externalsurface so as to prevent the movement of a substantial amount of a freeflowing fluid, such as water, from the hollow interior to the outside ofthe cage 9910, and to completely prevent the movement of a more viscousmaterial, such as a FPM or bone grafting material, from the hollowinterior to the outside of the cage 9910. It is also an aspect of thepresent disclosure for the at least one ridge 9922 to be configured toallow the veneer(s) 9924 to be freely removable from the externalsurface of the top and/or bottom wall 9912, 9914 and replaceable ontothe external surface of the top and/or bottom wall 9912, 9914 numeroustimes with no loss of function whatsoever. It is therefore preferablefor the at least one ridge 9922 to be configured so as to allow theveneer(s) 9924 to move into and out of place along the external surfacea plurality of times and to still hold the veneer(s) 9924 in placesufficiently snugly to at least substantially prevent the movement of aviscous material from the hollow interior to the outside of the cage9910. By way of example only, the veneer(s) 9924 are configured toslideably engage the cage 9910 by way of the at least one ridge 9922.

The veneer 9924 may be configured to be used with any number of cageconfigurations, shapes and sizes. For example, the veneer 9924 may be ofa generally rectangular or square configuration and thus operable withthe rectangular or square embodiments of the cage 9910 of the presentdisclosure described above. Additionally, the veneer 9924 may be shapedin a cylindrical, tubular, conical, circular, arced or rounded manner soas to be operable with the cylindrical or rounded embodiments of thecage 9940 of the present disclosure described below. For purposes of thepresent disclosure, the veneer 9924 may be of any shape and/or sizedesired including, without limitation, square, rectangular, triangular,round, circular, tubular, cylindrical, polygonal, conical, and any othershape that may be of use with an implantable intervertebral fusion cage9910 of the present disclosure. With specific reference now to FIGS. 3and 4, an example of a veneer 9924 is shown with a tab 9926 according toone embodiment of the present disclosure. The veneer 9924 preferablyincludes a projection or tab 9926 located at one end that projectsbeyond the outer perimeter of the cage 9910 and which serves tofacilitate removal of the veneer 9924 after implantation of the cage9910. For example, a user may grasp the projection or tab 9926 at thedesired time of removal and pull it in order to remove the veneer 9924from being in contact with the ridge(s) 9922. Optionally, the veneer9924 may also include an opening or hole (not shown) through which aline or thread may be tied, or a surgical instrument may be inserted, inorder to facilitate removal of the veneer 9924 from the cage 9910. FIG.17A shows a top aspect view of the veneer 9924 with the associated tab9926. A person having skill in the art will appreciate that the tab 9926may be of a material and dimensions (thickness, width, and length)different than that of the veneer 9924. The veneer 9924 is shown to havea width W2 and a length L2. FIG. 17B shows a side aspect view of theveneer 9924 with the associated tab 9926. The veneer 9924 is shown tohave a thickness T. In one embodiment of the present disclosure, thethickness T of the veneer 9924 is preferably between 0.4 mm and 0.75 mminclusive.

The at least one ridge 9922 may be configured in any number of mannersthat will allow the ridge 9922 to hold the veneer 9924 snugly to theexternal surface and to allow for the free removal and replacement ofthe veneer 9924 numerous times with no loss in function. In theembodiment described above and referring specifically to FIGS. 18A and18B, the ridge 9922 is comprised of a projection of the followinggeneral L-shaped configuration:

-   -   ┌

In these embodiments, the bottom portion 9928 of the ridge 9922 projectsgenerally perpendicularly from the top wall 9912 of the cage 9910, at ornear the intersection between the top wall 9912 and side wall 9916. Theupper (or overhang) portion 9930 of the ridge 9922 extendsperpendicularly from the bottom portion 9928 and projects over the topwall 9912 of the fusion cage 9910 in such a way so that the veneer 9924slides under the overhang 9930 of the ridge 9922 and is held in place bymaking contact with the overhang 9930. The overhang portion 9930 of thisembodiment may vary in angle, though it is preferable that the overhangportion be at a 90 degree angle relative to the bottom portion 9928.

In still other embodiments and referring specifically to FIG. 19A, theridge 9922 may be configured to secure a veneer 9924 on two sides. Theridge 9922 of these embodiments has the following general T-shapedconfiguration:

-   -   T

In these embodiments, the bottom portion 9928 of the ridge 9922 projectsgenerally perpendicularly from the top wall 9912 of the cage 9910 andthe upper portion (crossbar) 9932, projects generally perpendicularlyand outward from the bottom portion 9928 in two directions, so that aveneer 9924 can slide under either side of the crossbar 9932 of theridge 9922 and be held in place by the crossbar 9932. It is preferablefor the crossbar portion 9932 of these embodiments to be at a 90 degreeangle relative to the bottom portion 9928. This embodiment of the ridge9922 is particularly useful with cages of a round or cylindricalconfiguration, as described below, though they may also be used in anyof the embodiments of the present disclosure.

Referring to FIG. 19B, in some embodiments the ridge 9922 is a singleprojection that extends outward from the external surface of the topwall 9912 (forming an acute angle θ with the top wall 9912) such thatthe veneer 9924 slides under the ridge 9922 and is held in place untilsuch time as the veneer 9924 is removed from under the ridge 9922. Inthese embodiments, the angle θ may be configured to fit a specificveneer 9924. By way of example only, the angle θ is an acute angleranging from about zero degrees to about 45 degrees, or more preferablyfrom about 15 degrees to about 35 degrees. In these embodiments, theveneer 9924 is held in place under the ridge 9922 strictly by the angleθ of the ridge 9922, which makes contact with the veneer 9924 along theunderside of the ridge 9922 and holds the veneer 9924 snugly to theexternal surface of the top wall 9912.

Although shown and described above as having a configuration in which apair of ridges 9922 is provided on either or both of the top and bottomwalls 9912, 9914 in order to secure the veneer 9924 in place, otherconfigurations are possible. For example, FIGS. 20A and 20B illustratean example of a fusion cage 9910 in which three ridges 9922 are provideon at least the top wall 9912. The three ridges 9922 are provided at ornear the intersection of the top wall 9912 with three of the side walls9916 such that the veneer 9924, when inserted, is secured along threeedges 9934 of the veneer 9924. The only edge of the generallyrectangular veneer 9924 (shown by way of example only) that is notsecured by a ridge 9922 is the trailing edge 9936 containing the tabmember 9926. This configuration may be advantageous in that it providessecurity of the veneer 9924 along three edges 9934, including theleading edge 9934, helping to ensure that the veneer 9924 does notinadvertently “catch” on any anatomical structures as it is beingadvanced into the intervertebral space.

Referring to FIGS. 21A, 21B and 21C, a further alternative example of afusion cage 9910 is a provided, with one or more belt ridges 9938extending across the top wall 9912 from one of the side walls 9916 toanother of the side walls 9916. The one or more belt ridges 9938 areshown by way of example extending across the opening or fenestration9920. However, other configurations are possible. For example, one beltridge 9938 may be provided across the top wall 9912 proximate to thetrailing wall 9916, while at least one ridge 9922 is provided on the topwall 9912 proximate at least one of the other side walls 9916. In such afashion, the veneer 9924 would be secured along at least two edges 9934,or along one edge 9934 and the top surface 9940 of the veneer 9924. Asillustrated in FIG. 21C, an alternative embodiment of the fusion cage9910 may be provided having at least one belt ridge 9938 extending overeach of the top and bottom walls 9912, 9914.

Referring to FIGS. 22A and 22B, an example of a surgically implantableintervertebral fusion cage 9940 having a hollow frame that issubstantially tubular, cylindrical or conical in shape is providedaccording to one embodiment of the present invention. For the sake ofsimplicity, the cylindrical cage will be referred to herein as having amain wall 9942 that is tubular, cylindrical, or conical in shape and/orconfiguration, a first end wall 9944 and a second end wall 9946, eachend wall 9944, 9946 being interconnected with the main wall 9942 so asto form a closed tube, cylinder, or cone in that the main wall 9942 isconnected to the first end wall 9944 and to the second end wall 9946 insuch a way that the main wall 9942, first end wall 9944 and second endwall 9946, when fully interconnected, define a hollow interior 9948 tothe cage 9940 that is tubular, cylindrical or conical in shape and/orconfiguration. Preferably, the intervertebral fusion cage 9940 of thepresent embodiment has a diameter ranging from about 8 mm to about 18 mmand a length ranging from about 18 mm to about 40 mm. Thus, both thefirst end wall 9944 and the second end wall 9946 preferably have adiameter that ranges from about 8 mm to about 18 mm and the main wallhas a length that ranges from about 18 mm to about 40 mm. When fullyconstructed, the tubular, cylindrical or conical shaped cages have anelongated appearance such that they are longer than they are tall,making the largest points of contact of the cage with the targetvertebrae two arcs along the external surface of the main wall 9942, oneat the top of the surgical site that makes contact with one of thetarget vertebrae and one at the bottom of the surgical site that makescontact with a second target vertebra. The first end wall 9944 and thesecond end wall 9946 may also make contact with the target vertebrae,though it is preferable that the major points of contact with the targetvertebrae will occur via the exterior surface of the main wall 9942.

The main wall 9942 has at least one opening or fenestration 9950, andpreferably a plurality of openings or fenestrations 9950, located alongits length that provide a location, or locations, where material that isplaced or stored inside of the hollow interior 9948 may freely move fromthe hollow interior 9948 to the exterior of the cage 9940. The at leastone opening or fenestration 9950 thus allows for fluid communicationbetween the hollow interior 9948 of the cage 9940 and the outside of thecage 9940 in a similar manner as described above.

Additionally, the exterior surface of the main wall 9942 has at leastone ridge 9952 located on it, which is configured to hold at least oneshield or veneer 9954 in place along the exterior surface of the mainwall 9942. In some embodiments, as illustrated by way of example only inFIG. 22A, a single, T-shaped ridge 9952 runs the entire length of theexterior surface of the main wall 9942 such that a single shield orveneer 9954 can be wrapped around the full exterior circumference of themain wall 9942 and be held in place by making contact with both sides ofthe T-shaped ridge 9952. As stated above, all embodiments of the ridge9952 may be used to secure one or more veneers 9954 to the externalsurface of a cage 9940 of these embodiments, though the embodiment ofthe ridge 9954 that is particularly useful for a cage 9940 of this shapeand/or configuration is the T-shaped ridge 9954 shown and describedabove. In other embodiments and with specific reference now to FIG. 22B,the external surface has at least one ridge 9952, and may also have aplurality of ridges 9952, located thereon and there may be two ridges9952 running the length of two opposing sides of the external surface ofthe main wall 9942 such that two veneers 9954, a first veneer 9954 a anda second veneer 9954 b, are held in place along two opposing sides ofthe external surface of the main wall 9942. In one embodiment, there area plurality of ridges 9952 holding the veneer(s) 9954 in place, at leastone ridge 9952 running the length of the external surface of the mainwall 9942 as previously described and at least one ridge (not shown)located in a belt-like fashion around the entire perimeter of theexternal surface of the main wall 9942 such that the veneer 9954 slidesunder the at least one belt-like ridge, makes contact with the other atleast one ridge 9954, and is held in place accordingly.

As mentioned above, the main wall 9942 has at least one, and preferablya plurality of, openings or fenestrations 9950 formed therein that allowfor the movement of material out of the hollow interior 9948 and towardthe target vertebrae. Therefore, when a veneer 9954 is held in place bya ridge 9952 along the exterior surface of the main wall 9942, theveneer 9954 at least partially blocks or covers, and preferablycompletely blocks or covers, the at least one opening or fenestration9950 located along and through the main wall 9942. When the at least oneopening or fenestration 9950, and preferably the plurality of openingsor fenestrations 9950, are covered or blocked in this manner, the veneer9954 serves to prevent the movement of material as previously described.Additionally, when the veneer 9954 is removed from contact with theridge(s) 9952 located along the external surface of the main wall 9942,fluid communication is restored as previously described.

Further description of the features disclosed herein will continue inreference to the example of the interbody fusion cage 9910 having ridges9922 disclosed above in relation to FIGS. 16A and 16B, however thediscussion that follows applies equally to the fusion cage 9940 havingridges 9952 disclosed above in relation to FIGS. 22A and 22B. The ridges9922 of the present disclosure may be present along the external surfaceof the cage 9910 in any number of manners. For example, in someembodiments the ridges 9922 are cast with the cage 9910 as an extensionof the external surface of the top and/or bottom walls 9912, 9914 of thecage 9910 itself, thereby making the ridge 9922 a continuous physicalextension of the cage 9910. In other embodiments, the ridge 9922 isground out of or machined out of the exterior surface of the cage wall.In these embodiments, the ridge 9922 may be ground out or machined outat the time the cage 9910 is ground out or machined out of a portion ofa larger material, or the ridge 9922 may be ground out or machined outin advance of implantation in order to provide a customized ridge 9922.In still other embodiments, the ridge 9922 may be a separate piece thatis attached to, or secured onto, the external surface of the cage 9910prior to implantation. The ridge 9922 of these embodiments may besecured onto the external surface by any one or more of many standardmeans by which two structures may be operably connected together, suchas with the use of adhesives, welding, bands, straps, threading, aclamp, a snap-fit assembly, a bolted or screwed connection, apush-on/turn-on self-locking fastener, a press fit, rivets, and/orother, similar means. In other embodiments of the present disclosure,the ridge 9922 may be present on an internal surface of the cage 9910.

The surgically implantable intervertebral fusion cage 9910 of thepresent invention, inclusive of the ridges 9922 disclosed herein, may bemade of any kind of material suitable for surgical implantation that isalso sufficiently rigid so as to provide the required support betweenthe target vertebrae, such as steel or medical grade plastic. In someembodiments, the ridge 9922 is an integral part of the cage 9910 and thetwo structures are cast as a single, continuous unit. The cages 9910 andthe ridges 9922 may be made of: surgical stainless steel of the generalalloy type of iron, carbon, chromium (12-20%), molybdenum (0.2-3%), andnickel (8-12%); martensitic steel; 316L or 316LVM austenitic steel;and/or 316 surgical steel. It is desirable for the cages 9910 and ridges9922 of the present invention to be quite rigid and strong inconstruction so as to prevent any deforming during use and/or aftersurgical implantation, which can cause a loss of function.

The veneers 9924 of the present invention may be made of any kind ofmaterial suitable for surgical implantation that is rigid enough tocompletely prevent the movement of viscous materials from the hollowinterior when the veneer 9924 is in place along the exterior surface,but that is also sufficiently flexible so as to be readily removable andreplaceable without being damaged or deformed in any way. Suitablematerials include plastic, poly(tetrafluoroethene) orpoly(tetrafluoroethylene), or plastic, though the veneers 9924 may alsobe made of polyamide, polyethylene, polypropylene, polyphenylenesulfide, polyurethane, poly(tetrafluoroethylene), polyvinyl chloride,polyvinylidene fluoride or polyetheretherketone (PEEK).

In accordance with at least some aspects of at least one embodiment ofthe present invention, a method of surgically implanting anintervertebral fusion cage 9910 into a patient is provided. The methodcomprises first obtaining a surgically implantable intervertebral fusioncage 9910 having at least one wall (for example top wall 9912), at leastone ridge 9922 located on an exterior surface of the at least one wall9912, and at least one removable shield or veneer 9924. The at least onewall 9912 defines a hollow interior to the cage 9910 and has at leastone opening or fenestration 9920 in it that allows for fluidcommunication between the hollow interior and an exterior of the cage9910. The ridge 9922 is operable to hold the at least one veneer 9924 incontact with the exterior surface and is configured to allow the atleast one veneer 9924 to be freely removed from, and replaced onto, theexterior surface of the wall 9912.

The next step of the method is to prepare the cage 9910 for surgicalimplantation by filling the hollow interior with a material capable offusing two bony structures, preferably two vertebrae, and morepreferably two adjacent vertebrae, together. For example this materialmay be an orthopedic matrix containing additional fusion-promotingmaterial (FPM), for example including but not limited to calciumhydroxyapatite, bone morphogenic protein (BMP), demineralized bonematrix, collagen bone graft matrix (e.g. Formagraft®) and stem cellmaterial (e.g. Osteocel®) or other fusion-promoting substance placedwithin the spaces of the implant. The next step is contacting the atleast one veneer 9924 with the exterior surface of the cage 9910 bypositioning the veneer 9924 under at least a portion of the at least oneridge 9922 such that the at least one veneer 9924 is contacted with andheld in place along the exterior surface of the top wall 9912 by the atleast one ridge 9922 by way of such contact. Preferably, when the atleast one veneer 9924 is contacted with the at least one ridge 9922, theveneer 9924 at least partially covers or blocks the at least one openingor fenestration 9920, preventing fluid communication between the hollowinterior and the exterior of the cage 9910, and preventing the materialfrom leaving the hollow interior.

After the cage 9910 has been prepared for implantation, the next step ofthe method is to locate an appropriate surgical site in a patient forimplantation of the cage 9910. The surgical site may be anintervertebral location, including the space typically filled by anintervertebral disc, but may also be any location in a patient where twobony structures are to be fused together. The next step in the method isto create a surgical opening and operative corridor in the patient thatwill accommodate the cage 9910. This opening may be made dorsally,ventrally, laterally or at any other location along the patient that ismedically efficacious to grant the user access to the surgical site.Once the opening is created, the next step in the method is tosurgically implant the cage 9910 into the patient and then position itin the surgical site between the desired bony structures, and preferablybetween the two adjacent vertebrae of interest, in such a way that willserve to utilize the material in connection with the patient's ownsystems to promote the fusion of the two bony structures by way of, andthough, the cage 9910. Thereafter, the at least one veneer 9924 isremoved from contact with the ridge and the exterior surface of the cage9910, thereby restoring fluid communication between the hollow interiorand the exterior of the cage 9910 and allowing the material to move fromthe hollow interior to the exterior of the cage 9910. Once these tasksare completed, the method is concluded by closing the surgical openingin the patient.

Embodiments of the present invention may comprise any one or more of thenovel features described herein, included in the Detailed Description,included in the Brief Summary of the Invention and/or shown in thedrawings. The claims may include one or more features of any one or moreof the embodiments described herein. For example, one or more featuresof one embodiment may be claimed in combination with one or morefeatures of another embodiment, and no portion of this specificationlimits such claims.

The present inventions, in various embodiments, include components,methods, processes, systems and/or apparatuses substantially as depictedand described herein, including various embodiments, subcombinations,and subsets thereof. Those of skill in the art will understand how tomake and use the present inventions after understanding the presentdisclosure. The present inventions, in various embodiments, includeproviding devices and processes in the absence of items not depictedand/or described herein or in various embodiments hereof, including inthe absence of such items as may have been used in previous devices orprocesses, e.g., for improving performance, achieving ease and\orreducing cost of implementation.

The foregoing discussion of the inventions has been presented forpurposes of illustration and description. The foregoing is not intendedto limit the inventions to the form or forms disclosed herein. In theforegoing Detailed Description for example, various features of theinventions are grouped together in one or more embodiments for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimed inventionsrequire more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the followingclaims are hereby incorporated into this Detailed Description by thisreference, with each claim standing on its own as a separate preferredembodiment of the inventions.

Moreover though the description of the inventions has includeddescriptions of one or more embodiments and certain variations andmodifications, other variations and modifications are within the scopeof the inventions, e.g., as may be within the skill and knowledge ofthose in the art, after understanding the present disclosure. It isintended to obtain rights which include alternative embodiments to theextent permitted, including alternate, interchangeable and/or equivalentstructures, functions, ranges or steps to those claimed, whether or notsuch alternate, interchangeable and/or equivalent structures, functions,ranges or steps are disclosed herein, and without intending to publiclydedicate any patentable subject matter.

What is claimed is:
 1. A system for performing spinal fusion,comprising: an intervertebral fusion cage having a frame that comprisesa top wall, a bottom wall, a leading end, a trailing end, and a pair oflateral walls, the intervertebral fusion cage having a hollow interiorand an exterior, and the top wall and the bottom wall each have at leastone opening allowing for fluid communication between the hollow interiorand an exterior, said cage configured for receiving in its interior afusion promoting material comprising bone graft material, for placementwithin the hollow interior of the fusion cage; said cage adapted toreceive generally planar elements disposed on at least one of the topwall, bottom wall, and pair of lateral walls of the cage, said generallyplanar elements configured to reversibly cover the at least one openingin one of the top wall and the bottom wall, said generally planarelements preventing leakage of the fusion promoting material out of theat least one opening, said generally planar elements providing a barrierto the undesired translocation of the fusion-promoting material andsubstantially precluding fluid communication between the hollow interiorand the exterior of the cage, such that said fusion promoting materialis maintained within the hollow interior of the intervertebral fusioncage during insertion of the intervertebral fusion cage into theintervertebral space, wherein said generally planar elements areconfigured to be removable from the intervertebral fusion cage when theintervertebral fusion cage is placed in the intervertebral space,wherein fluid communication is permitted between the hollow interior andthe exterior of the cage and allows the fusion promoting material tomove from the hollow interior to the exterior of the cage, wherein saidintervertebral fusion cage includes a first aperture formed in saidtrailing end, said first aperture configured to mate with an inserter,and wherein the generally planar elements comprise veneers that aredisposed on either side of a fusion implant having more than oneaperture adapted for receiving fusion-promoting material.
 2. The systemas set forth in claim 1, wherein the veneers are held in place so as toprevent unintended movement of the veneers during surgical implantationof the cage.
 3. The system as set forth in claim 1, wherein the veneersare removed from the cage upon surgical implantation of the cage.
 4. Thesystem as set forth in claim 1, wherein fusion promoting material flowsfrom the interior of the cage out of the openings and into contact withtarget vertebrae on the top of the cage and at the bottom of the cage,and the veneers retain a portion of the material inside the hollowinterior sufficient to promote fusion of the target vertebrae by thegeneration of osseous tissue through and around the fusion cage.
 5. Asystem for performing spinal fusion, comprising: an intervertebralfusion cage having a frame that comprises a top wall, a bottom wall, aleading end, a trailing end, and a pair of lateral walls, theintervertebral fusion cage having a hollow interior and an exterior, andthe top wall and the bottom wall each have at least one opening allowingfor fluid communication between the hollow interior and an exterior,said cage configured for receiving in its interior a fusion promotingmaterial comprising bone graft material, for placement within the hollowinterior of the fusion cage; said cage adapted to receive generallyplanar elements disposed on at least one of the top wall, bottom wall,and pair of lateral walls of the cage, said generally planar elementsconfigured to reversibly cover the at least one opening in one of thetop wall and the bottom wall, said generally planar elements preventingleakage of the fusion promoting material out of the at least oneopening, said generally planar elements providing a barrier to theundesired translocation of the fusion-promoting material andsubstantially precluding fluid communication between the hollow interiorand the exterior of the cage, such that said fusion promoting materialis maintained within the hollow interior of the intervertebral fusioncage during insertion of the intervertebral fusion cage into theintervertebral space, wherein said generally planar elements areconfigured to be removable from the intervertebral fusion cage when theintervertebral fusion cage is placed in the intervertebral space,wherein fluid communication is permitted between the hollow interior andthe exterior of the cage and allows the fusion promoting material tomove from the hollow interior to the exterior of the cage, wherein saidintervertebral fusion cage includes a first aperture formed in saidtrailing end and wherein said first aperture is threaded, wherein thegenerally planar elements comprise veneers that are disposed on eitherside of a fusion implant having more than one aperture adapted forreceiving fusion-promoting material, and wherein the bottom wall has aplurality of openings that provide access to the hollow interior of thecage and that allow for fluid communication between the hollow interiorand the exterior of the cage, said plurality of openings permitting afusion-promoting material that is inserted into the hollow interiorprior to surgical implantation, to leave the hollow interior of thecage, make contact with desired vertebrae and promote the fusion of thedesired vertebrae.
 6. The system as set forth in claim 5, wherein theveneers are held in place so as to prevent unintended movement of theveneers during surgical implantation of the cage.
 7. The system as setforth in claim 5, wherein the veneers are removed from the cage uponsurgical implantation of the cage.
 8. The system as set forth in claim5, wherein fusion promoting material flows from the interior of the cageout of the openings and into contact with target vertebrae on the top ofthe cage and at the bottom of the cage, and the veneers retain a portionof the material inside the hollow interior sufficient to promote fusionof the target vertebrae by the generation of osseous tissue through andaround the fusion cage.